| Water Agency | Type | Office | County |
| Alameda County Flood Control & Water Conservation District, Zone 7 | County & Spec. Dist. | Pleasanton | Alameda |
| Alameda County Water District | Special District | Fremont | Alameda |
| Alpaugh Irrigation District | Special District | ||
| Alpine Springs County Water District | Special District | Tahoe City | |
| Alta Irrigation District | Special District | ||
| Amador County Department of Water Resources | Special District | Jackson | Amador |
| Amador Water Agency | Special District | Jackson | Amador |
| American River Flood Control District | Special District | Sacramento | |
| American States Water Company | NGO | ||
| American Water Works Service | NGO | National City | San Diego |
| Anaheim Water | City | Anaheim | Orange |
| Anderson-Cottonwood Irrigation District | Special District | ||
| Angiola Water District | Special District | ||
| Antelope Valley-East Kern Water Agency | Special District | Quartz Hill | LA-Kern |
| Apple Valley Foothill County Water District | Special District | Apple Valley | San Bernardino |
| Apple Valley Heights County Water District | Special District | Apple Valley | San Bernardino |
| Arcade Water District | Special District | Sacramento | |
| Armstrong Valley Water Company | NGO | Guerneville | |
| Aromas Water District | Special District | Aromas | Santa Clara |
| Arvin-Edison Water Storage District | Special District | Arvin | |
| Atascadero Mutual Water District | Special District | Atascadero | |
| Azurix | NGO | Los Angeles | Los Angeles |
| Azusa Light & Water | City | Azusa | LA |
| Baldy Mesa Water District | Special District | Victorville | LA |
| Banta-Carbona Irrigation District | Special District | ||
| Bard Water District | Special District | ||
| Bass Lake Water Company | NGO | Bass Lake | |
| Bear Valley Community Services District | Special District | Tehachapi | Kern |
| Bear Valley Water District | Special District | Redlands | San Bernardino |
| Beaumont-Cherry Valley Water District | Special District | Cherry Valley | Riverside |
| Bella Vista Water District | Special District | ||
| Belmont County Water District | Special District | Belmont | |
| Belridge Water Services District | Special District | Bakersfield | Kern |
| Belridge Water Storage District | Special District | ||
| Berrenda Mesa Water District | Special District | Bakersfield | Kern |
| Big Bear Area Regional Wastewater Agency | Special District | Big Bear City | San Bernardino |
| Big Bear City Community Services District | Special District | Big Bear City | San Bernardino |
| Big Bear Municipal Water District | Special District | Big Bear City | San Bernardino |
| Big Pine Community Service | Special District | Big Pine | |
| Biggs-West Gridley Water District | Special District | Gridley | |
| Bighorn-Desert View Water Agency | Special District | Landers | San Bernardino |
| Bodega Bay Public Utilities District | Special District | Bodega Bay | |
| Bolinas Community Public Utility District | Special District | ||
| Boron Community Services District | Special District | Boron | San Bernardino |
| Borrego Water District | Special District | Borrego Springs | San Diego |
| Bridgeport Public Utilities District | Special District | Bridgeport | |
| Broadview Water District | Special District | ||
| Brooktrails Township Community Services District | Special District | Willits | |
| Brophy Water District | Special District | Marysville | |
| Browns Valley Irrigation District | Special District | Browns Valley | |
| Buellton Community Services District | Special District | Buellton | |
| Buena Vista Water Storage District | Special District | Buttonwillow | |
| Bueno Colorado Municipal Water District | Special District | Vista | San Diego |
| Burney Water District | Special District | Burney | |
| Butte Water District | Special District | ||
| Byron-Bethany Irrigation District | Special District | Byron | |
| Cachuma Operation and Maintenance Board | Special District | ||
| Cachuma Operations & Maintenance | Special District | Santa Barbara | Santa Barbara |
| Cadiz Inc. | NGO | Los Angeles | LA |
| Calaveras County Water District | Special District | San Andreas | Calaveras |
| Calaveras Public Utilities District | Special District | San Andreas | Calaveras |
| California Avocado Commission | NGO | ||
| California Domestic Water Company | NGO | Whittier | LA |
| California Water Service Company | NGO | San Jose | Santa Clara |
| California-American Water Company | NGO | ||
| Calleguas Municipal Water District | Special District | Thousand Oaks | Ventura |
| Calpella County Water District | Special District | Calpella | |
| Cambria Community Services District | Special District | Cambria | |
| Camp Far West Irrigation District | Special District | ||
| Camrosa Water District | Special District | Camarillo | Ventura |
| Capistrano Beach Water District | Special District | Capistrano | Orange |
| Capistrano Valley Water District | Special District | San Juan Capistrano | Orange |
| Carlsbad MWD | Special District | Carlsbad | San Diego |
| Carmichael Water District | Special District | Carmichael | |
| Carminteria County Water District | Special District | Carpinteria | Santa Barbara |
| Carpenter Irrigation District | Special District | Orange | Orange |
| Carpinteria Valley Water District | Special District | Carpinteria | Santa Barbara |
| Casitas Municipal Water District | Special District | Oak View | |
| Castaic Lake Water Agency | Special District | Santa Clarita | LA |
| Castroville Water District | Special District | Castroville | |
| Cawelo Water District | Special District | Bakersfield | Kern |
| Centerville Community Services District | Special District | ||
| Central Basin MWD | Special District | Carson | LA |
| Central California Irrigation District | Special District | Los Banos | |
| Central Coast Water Authority | Special District | ||
| Central San Joaquin Water Conservation District | Special District | Stockton | |
| Central Water District | Special District | ||
| Channel Islands Beach Community Services District | Special District | Channel Island | Ventura |
| Chester Public Utilities District | Special District | Chester | |
| Chino Basin Water Conservation District | Special District | Chino | San Bernardino |
| Chino Basin Watermaster | Special District | San Bernardino | |
| Chowchilla Water District | Special District | ||
| Circle Oaks County Water District | Special District | ||
| Citrus Heights Water District | Special District | Citrus Heights | LA |
| City of Adelanto | City | Adelanto | San Bernardino |
| City of Alhambra | City | Alhambra | LA |
| City of Anderson | City | Anderson | |
| City of Arcata | City | Arcarta | |
| City of Bellflower | City | Bellflower | LA |
| City of Beverly Hills | City | Beverly Hills | LA |
| City of Brea | City | Brea | Orange |
| City of Brentwood Public Works | City | Brentwood | LA |
| City of Buellton | City | Buellton | |
| City of Buena Park | City | Buena Park | Orange |
| City of Camarillo | City | Camarillo | Ventura |
| City of Cotati | City | Cotati | |
| City of Escondido | City | Escondido | San Diego |
| City of Fairfield | City | Fairfield | |
| City of Fallbrook | City | Fallbrook | San Diego |
| City of Fresno Water Division | City | Fresno | Fresno |
| City of Hanford | City | Hanford | |
| City of Huntington Beach | City | Huntington Beach | Orange |
| City of Lakeport | City | Lakeport | |
| City of Lakewood | City | Lakewood | LA |
| City of Morgan Hill | City | Morgan Hill | Santa Clara |
| City of Norwalk | City | Norwalk | LA |
| City of Oceanside | City | Oceanside | San Diego |
| City of Palo Alto | City | Palo Alto | |
| City of Pittsburg | City | Pittsburg | |
| City of Pomona | City | Pomona | LA |
| City of Poway | City | Poway | San Diego |
| City of Redding Water Utility | City | Redding | |
| City of Riverside | City | Riverside | Riverside |
| City of Roseville | City | Roseville | |
| City of Running Springs | City | Running Springs | |
| City of Sacramento Utilities Department | City | Sacramento | Sacramento |
| City of San Bernardino Municipal Water Department | City | San Bernardino | San Bernardino |
| City of Santa Barbara | City | Santa Barbara | Santa Barbara |
| City of Santa Cruz Water Department | City | Santa Cruz | Santa Cruz |
| City of Santa Rosa | City | Santa Rosa | Santa Rosa |
| City of South Pasadena Water Department | City | S. Pasadena | LA |
| Clawa County Water District | Special District | Fresno | |
| Clear Creek Community Services District | Special District | ||
| Coachella Valley Water District | Special District | Coachella | Riverside |
| Coastside County Water District | Special District | Half Moon Bay | |
| Colusa Basin Drainage District | Special District | Arbuckle | |
| Colusa County Water District | Special District | Arbuckle | Colusa |
| Consolidated Irrigation District | Special District | ||
| Contra Costa County Water Agency | Special District | Martinez | Contra Costa |
| Contra Costa Water District | Special District | Concord | Contra Costa |
| Corcoran Irrigation District | Special District | Corcoran | |
| Cordua Irrigation District | Special District | Marysville | |
| Corning Water District | Special District | Corning | |
| Corona Water Utility | City | Corona | Riverside |
| Cottonwood Water District | Special District | Cottonwood | |
| County of Contra Costa | County | Martinez | Contra Costa |
| Covina Irrigating Company | NGO | Covina | LA |
| Crescenta Valley Water District | Special District | La Crescenta | LA |
| Crestline Sanitation District | Special District | Crestline | San Bernardino |
| Crestline Village Water District | Special District | Crestline | San Bernardino |
| Crestline-Lake Arrowhead Water Agency | Special District | Crestline | San Bernardino |
| Cucamonga County Water District | Special District | Rancho Cucamonga | San Bernardino |
| Cucamonga County WD | Special District | Rancho Cucamonga | San Bernardino |
| Deer Creek and Tule River Authority | Special District | ||
| Del Paso Manor Water District | Special District | Sacramento | |
| Del Puerto Water District | Special District | ||
| Delano-Earlimart Irrigation District | Special District | ||
| Delhi County Water District | Special District | ||
| Delta Diablo Sanitary District | Special District | ||
| Descanso Community Water District | Special District | Descanso | |
| Desert Water Agency | Special District | Palm Springs | Riverside |
| Devil's Den Water District | Special District | Santa Clarita | LA |
| Devore Mutual Water Company | NGO | Devore | |
| Diablo Water District | Special District | ||
| Donner Lake Utility Company | NGO | Truckee | |
| Dublin San Ramon Services District | Special District | Dublin | Alameda-Contra Costa |
| Ducor Community Services District | Special District | ||
| Dudley Ridge Water District | Special District | Fresno | |
| Dunnigan Water District | Special District | Dunnigan | |
| East Bay Municipal Utilities District | Special District | Oakland | Alameda |
| East Blythe County Water District | Special District | Blythe | |
| East Contra Costa Irrigation District | Special District | Brentwood | Contra Costa |
| East Niles Community Services District | Special District | Bakersfield | Kern |
| East Orange County Water District | Special District | Orange | Orange |
| East Pasadena Water Company | NGO | Pasadena | LA |
| East Valley Water District | Special District | San Bernardino | San Bernardino |
| Eastern Municipal Water District | Special District | Perris | Riverside |
| Eastside Water District | Special District | ||
| El Dorado County Water Agency | Special District | Placerville | El Dorado |
| El Dorado Irrigation District | Special District | El Dorado | |
| El Nido Irrigation District | Special District | El Nido | |
| El Toro Water District | Special District | Lake Forest | Orange |
| Elsinore Valley MWD | Special District | Elsinore | Riverside |
| Empire West Side Irrigation District | Special District | Stratford | |
| Encina Water Pollution Control Facility | Special District | ||
| Erskine Creek Water Company | NGO | Lake Isabella | |
| Escondido Water/Sewer | City | Escondido | San Diego |
| Exeter Irrigation District | Special District | ||
| Fair Oaks Water District | Special District | ||
| Fall River Mills Community Services District | Special District | Fall River | |
| Fallbrook Public Utilities District | Special District | Fallbrook | San Diego |
| Feather Water District | Special District | Yuba City | |
| Firebaugh Canal Water District | Special District | ||
| Foothill Municipal Water District | Special District | Flintridge | LA |
| Foresthill Public Utilities District | Special District | ||
| Forestville County Water District | Special District | Forestville | |
| Fountain Valley Public Works | City | Fountain Valley | Orange |
| Fox Canyon Groundwater Management Agency | Special District | Ventura | Ventura |
| Frazier Park Public Utilities District | Special District | ||
| Free Water County Water District | Special District | Sanger | |
| Fresno Irrigation District | Special District | Fresno | Fresno |
| Fresno Metropolitan Flood Control District | Special District | Fresno | Fresno |
| Friant Power Authority | Special District | ||
| Friant Water Users Authority | Special District | Lindsay | |
| Fruitridge Vista Water Company | NGO | Sacramento | |
| Fullerton Water | City | Fullerton | Orange |
| Garberville Water Company | NGO | Garberville | |
| Garden Grove DPW | City | Garden Grove | Orange |
| Georgetown Divide Public Utilities District | Special District | ||
| Glenn-Colusa Irrigation District | Special District | Willows | |
| Glide Water District | Special District | ||
| Golden Hills Community Services District | Special District | Tehachapi | Kern |
| Goleta Water District | Special District | Goleta | Santa Barbara |
| Graeagle Water Company | NGO | Graeagle | |
| Grassland Water District | Special District | Los Banos | |
| Gravelly Ford Water District | Special District | Madera | |
| Greenfield County Water District | Special District | Bakersfield | Kern |
| Heather Glen Community Services District | Special District | Applegate | |
| Heber Public Utility District | Special District | City | Imperial |
| Helix Water District | Special District | La Mesa | San Diego |
| Hesperia Water District | Special District | Hesperia | San Bernardino |
| Hetch Hetchy Water & Power | Special District | San Francisco- | |
| Hidden Valley Lake Community Services District | Special District | Middletown | |
| Hi-Desert Water District | Special District | Yucca Valley | San Bernardino |
| Highlands Water Company | NGO | Clearlake | |
| Hoopa Valley Public Utilities | Special District | Hoopa | |
| Humboldt Bay Municipal Water District | Special District | Humboldt | |
| Humboldt Community Services District | Special District | Cutten | Humboldt |
| Huntington Beach Water | City | Huntington Beach | Orange |
| Idyllwild Water District | Special District | San Bernardino | |
| Imperial ID | Special District | Imperial | Imperial |
| Imperial Irrigation District | Special District | Imperial | Imperial |
| Indian Wells Valley Water District | Special District | Ridgecrest | |
| Inland Empire Utilities Agency | Special District | Rancho Cucamonga | San Bernardino |
| Inyo County Water Department | County | Bishop | |
| Irvine Ranch Water District | Special District | Irvine | Orange |
| Ivanhoe Irrigation District | Special District | Visalia | |
| Ivanhoe Public Utilities District | Special District | Ivanhoe | |
| James Irrigation District | Special District | San Joaquin | |
| Joshua Basin Water District | Special District | ||
| June Lake Public Utilities District | Special District | ||
| Jurupa Community Services District | Special District | Riverside | Riverside |
| Kanawha Water District | Special District | ||
| Kaweah Delta Water Conservation District | Special District | ||
| Kaweah River Power Authority | Special District | Tulare | |
| Kern County Water Agency | Special District | Bakersfield | Kern |
| Kern Delta Water District | Special District | Kern | |
| Kern Water Bank Authority | Special District | Bakersfield | Kern |
| Kern-Tulare Water District | Special District | Kern-Tulare | |
| Keswick Community Services | Special District | Shasta | |
| Kings County Water District | Special District | Hanford | Kings |
| Kings River Conservation District | Special District | Fresno | Kings |
| Kings River Water District | Special District | Sanger | |
| Kinneloa Irrigation District | Special District | ||
| Kirkwood Meadows Public Utilities District | Special District | Kirkwood | |
| Knights Landing Ridge Drainage District | Special District | ||
| La Canada Irrigation District | Special District | La Canada Flintridge | LA |
| LA City Bureau of Sanitation | City | LA | LA |
| LA County San Districts | Special District | Whittier | LA |
| La Habra Heights County Water District | Special District | La Habra Hts | Orange |
| La Puente Valley County Water District | Special District | LA | |
| LA Stormwater Program | |||
| LADWP | City | LA | LA |
| LADWP Water | City | LA | LA |
| Laguna Beach County Water District | Special District | Laguna Beach | Orange |
| Laguna Beach Ocean Water | Special District | Laguna Beach | Orange |
| Laguna Irrigation District | Special District | Riverdale | |
| Laguna Niguel Public Works | City | Laguna Niguel | Orange |
| Lake Arrowhead Community Services District | Special District | Lake Arrowhead | San Bernardino |
| Lake County Flood Control & Water Conservation District | Special District | ||
| Lake Forest Public Works | City | Lake Forest | Orange |
| Lake Hemet Municipal Water District | Special District | Hemet | Riverside |
| Lake Shastina Mutual Water District | Special District | Weed | |
| Lakeside Irrigation Water District | Special District | ||
| Lakeside Water District | Special District | ||
| Las Flores Water Company | NGO | Altadena | LA |
| Las Virgenes MWD | Special District | Calabasas | LA |
| Laton Community Services District | Special District | ||
| Laytonville County Water District | Special District | Laytonville | |
| Le Grand Community Services District | Special District | ||
| Le Grand-Athlone Water District | Special District | ||
| Leucadia County WD | Special District | Leucadia | San Diego |
| Linda County Water District | Special District | Marysville | |
| Linden County Water District | Special District | Linden | |
| Lindmore Irrigation District | Special District | ||
| Lindsay-Strathmore Irrigation District | Special District | ||
| Littlerock Creek Irrigation District | Special District | Littlerock | |
| Long Beach Water | City | Long Beach | LA |
| Los Alamos Community Services District | Special District | ||
| Los Alisos Water District | Special District | Lake Forest | Orange |
| Los Angeles County Waterworks Districts | Special District | LA | LA |
| Los Angeles Department of Water and Power | Special District | LA | LA |
| Lost Hills Water District | Special District | Bakersfield | Kern |
| Lower San Joaquin Levee District | Special District | Dos Palos | |
| Lower Tule River Irrigation District | Special District | Woodville | |
| Madera Irrigation District | Special District | Madera | Madera |
| Madera Water District | Special District | Madera | Madera |
| Madera-Chowchilla Power Authority | Special District | Madera | Madera |
| Main San Gabriel Basin Watermaster | Special District | Azusa | LA |
| Maine Prairie Water District | Special District | ||
| Majestic Pines Community Services District | Special District | San Diego | San Diego |
| Malaga County Water District | Special District | Fresno | Fresno |
| Mammoth Community Water District | Special District | ||
| Mammoth County Water District | Special District | Mammoth | |
| Mariana Ranchos County Water District | Special District | Apple Valley | San Bernardino |
| Marin Municipal Water District | Special District | Corte Madera | Marin |
| Marina Coast Water District | Special District | Marina | |
| Mariposa County Water District | Special District | Mariposa | |
| Mariposa Public Utilities District | Special District | Mariposa | |
| Mariposa Public Utility District | Special District | Mariposa | |
| Marygold Mutual Water | Special District | Bloomington | |
| Maxwell Irrigation District | Special District | ||
| Maywood Mutual Water Company | NGO | Maywood | |
| McCloud Community Services | Special District | McCloud | |
| Meadow Vista County Water District | Special District | Meadow Vista | |
| Mendocino County Water Agency | Special District | Mendocino | |
| Merced Irrigation District | Special District | Merced | |
| Mesa Consolidated Water District | Special District | Costa Mesa | Orange |
| Metropolitan Water District of Southern California | Special District | LA | Coastal SoCal |
| Midway Heights County Water District | Special District | Midway | |
| Mil Potrero Mutual Water Company | NGO | Frazier Park | |
| Millview County Water District | Special District | Ukiah | |
| Mission Hills Community Services District | Special District | Lompoc | Santa Barbara |
| Mission Springs Water District | Special District | Desert Hot Springs | San Bernardino |
| Modesto Irrigation District | Special District | Modesto | |
| Mojave Public Utilities District | Special District | Mojave | San Bernardino |
| Mojave Water Agency | Special District | Apple Valley | San Bernardino |
| Montague Water Conservation District | Special District | Montague | |
| Monte Vista Water District | Special District | Montclair | San Bernardino |
| Montebello Land & Waer Company | NGO | Montebello | LA |
| Montecito Sanitary District | Special District | Santa Barbara | Santa Barbara |
| Montecito Water District | Special District | Santa Barbara | Santa Barbara |
| Monterey County Public Works-Community Service Area #75 | Special District | Salinas | Monterey |
| Monterey County Water Resources Agency | Special District | Salinas | Monterey |
| Monterey Peninsula Water Management District | Special District | Salinas | Monterey |
| Moulton Niguel WD | Special District | Laguna Niguel | Orange |
| Mountain Gate Community Services District | Special District | ||
| Municipal Water District of Orange County | Special District | Fountain Valley | Orange |
| Murrieta County Water District | Special District | Murrieta | |
| Nevada Irrigation District | Special District | ||
| Newhall County Water District | Special District | Newhall | LA |
| Newport Beach Public Works | City | Newport Beach | Orange |
| North Coast County Water District | Special District | Pacifica | |
| North Delta Water Agency | Special District | Sacramento | |
| North Kern Water Storage District | Special District | Bakersfield | Kern |
| North Marin Water District | Special District | Novato | Marin |
| North of the River Municipal Water District | Special District | Bakersfield | Kern |
| North San Joaquin Water Conservation District | Special District | Lodi | San Joaquin |
| Northridge Water District | Special District | Sacramento | Sacramento |
| Oakdale Irrigation District | Special District | ||
| Oceanside Water Utilities | City | Oceanside | San Diego |
| Oildale Mutual Water Company | NGO | Bakersfield | Kern |
| Ojai Basin Groundwater Management Agency | Special District | Ojai | Ventura |
| Olcese Water District | Special District | Bakersfield | Kern |
| Olivenhain MWD | Special District | Encinitas | San Diego |
| Omochumne-Hartnell Water District | Special District | Wilton | |
| Orange County Sanitation District | Special District | Fountain Valley | Orange |
| Orange County Water District | Special District | Fountain Valley | Orange |
| Orange Cove Irrigation District | Special District | ||
| Orange Public Works | City | Orange | Orange |
| Orchard Dale Water District | Special District | Whittier | LA |
| Orland-Artois Water District | Special District | Orland | |
| Orosi Public Utilities District | Special District | Orosi | |
| Oroville-Wyandotte Irrigation District | Special District | Oroville | |
| Otay Water District | Special District | Spring Valley | San Diego |
| Pacheco Water District | Special District | ||
| Padre Dam MWD | Special District | ||
| Pajaro Valley Water Management Agency | Special District | ||
| Pajaro/Sunny Mesa Community Services District | Special District | Watsonville | |
| Palm Ranch Irrigation District | Special District | Quartz Hill | |
| Palmdale Water District | Special District | Palmdale | LA |
| Palo Verde Irrigation District | Special District | ||
| Panoche Drainage District | Special District | Firebaugh | |
| Panoche Water District | Special District | Firebaugh | |
| Paradise Irrigation District | Special District | Paradise | |
| Park Water Co. | NGO | Downey | LA |
| Pasadena W&P | City | Pasadena | LA |
| Patterson Water District | Special District | ||
| Pebble Beach Community Services District | Special District | ||
| Pescadero Reclamation District #2058 | Special District | Tracy | |
| Pico Water District | Special District | Pico Rivera | LA |
| Pinedale County Water District | Special District | Pinedale | |
| Pinyon Pines County Water District | Special District | Mountain | |
| Pixley Irrigation District | Special District | Pixley | |
| Placer County Water Agency | Special District | Auburn | Placer |
| Plain View Water District | Special District | ||
| Planada Community Services District | Special District | Planada | |
| Pleasant Valley County Water District | Special District | Camarillo | Ventura |
| Pleasant Valley Water District | Special District | Coalinga | |
| Pomona-Walnut-Rowland Joint Water Line Commission | Special District | Pomona | LA |
| Port Hueneme Water Agency | Special District | Ventura | |
| Porterville Irrigation District | Special District | Porterville | |
| Poseidon Resources, Inc. | NGO | Long Beach | LA |
| Princeton-Codora-Glenn Irrigation District | Special District | ||
| Provident Irrigation District | Special District | ||
| Purissima Hills Water District | Special District | Los Altos Hills | |
| Quartz Hill Water District | Special District | ||
| Rag Gulch Water District | Special District | ||
| Rainbow MWD | Special District | Fallbrook | San Diego |
| Raisin City Water District | Special District | Raisin City | |
| Ramirez Water District | Special District | Marysville | |
| Ramona Municipal Water District | Special District | Ramona | San Diego |
| Rancho California Water District | Special District | Temecula | Riverside |
| Rand Communities Water District | Special District | Randsberg | |
| Reclamation District No. 2068 | Special District | Dixon | |
| Reclamation District No. 999 | Special District | Clarksburg | |
| Redwood Valley County Water District | Special District | Redwood Valley | |
| Richvale Irrigation District | Special District | Richvale | |
| Rincon del Diablo Municipal Water District | Special District | Escondido | San Diego |
| Rio Alto Water District | Special District | Cottonwood | |
| Rio Linda-Elverta Community Water District | Special District | ||
| Riverdale Irrigation District | Special District | Riverdale | |
| Riverside Public Utilities | City | Riverside | Riverside |
| Riverview Water District | Special District | Lakeside | |
| Rogina Water Company | NGO | Talmage | |
| Root Creek Water District | Special District | ||
| Rosamond Community Services District | Special District | ||
| Rosedale-Rio Bravo Water Storage District | Special District | ||
| Rowland Water District | Special District | Rowland Hts | LA |
| Rubio Canyon Land & Water Co. | NGO | Altadena | LA |
| Sacramento County Water Maintenance District | County | Sacramento | Sacramento |
| Sacramento Metropolitan Water Authority | Special District | Sacramento | Sacramento |
| Sacramento River West Side Levee District | Special District | Grimes | Sacramento |
| San Andreas Sanitary District | Special District | ||
| San Benito County Water District | Special District | Laguna Hills | Orange |
| San Benito County Water District | Special District | Hollister | San Benito |
| San Bernardino Valley Municipal Water District | Special District | San Bernardino | San Bernardino |
| San Bernardino Valley Water Conservation District | Special District | Redlands | San Bernardino |
| San Clemente Utilities | City | San Clemente | Orange |
| San Diego County Water Authority | Special District | San Diego | San Diego |
| San Diego Metro Waste- | City | San Diego | San Diego |
| San Diego Water Dep't | City | San Diego | San Diego |
| San Dieguito Water District | Special District | Encinitas | San Diego |
| San Francisco Public Utilities Commission | City | San Francisco | San Francisco |
| San Gabriel Basin Water Quality Authority | Special District | Covina | LA |
| San Gabriel County Water District | Special District | LA | |
| San Gabriel Valley Municipal Water District | Special District | Azusa | LA |
| San Gorgonio Pass Water Agency | Special District | LA | |
| San Joaquin County Flood Control & Water Conservation District | Special District | Stockton | San Joaquin |
| San Joaquin River Exchange Contractors Water Authority | Special District | Los Banos | |
| San Juan Basin Authority | Special District | San Juan Capistrano | Orange |
| San Juan Capistrano Public Works | |||
| San Juan Ridge County Water District | Special District | ||
| San Juan Water District | Special District | Granite Bay | |
| San Juan WD | |||
| San Lorenzo Valley County Water District | Boulder Creek | ||
| San Luis & Delta-Mendota Water Authority | Special District | ||
| San Luis Water District | Special District | Los Banos | |
| Santa Ana Mountain County Water District | Special District | Trabuco | Orange |
| Santa Ana Public Works | City | Santa Ana | Orange |
| Santa Ana Watershed Project Authority | Special District | Riverside | Orange-Riverside-San Bernardino |
| Santa Carbona Irrigation District | Special District | Tracy | |
| Santa Clara Valley Water District | Special District | San Jose | Santa Clara |
| Santa Clarita Water Company | NGO | Saugus | LA |
| Santa Fe Irrigation District | Special District | Rancho Santa Fe | |
| Santa Margarita WD | Special District | Las Flores | Orange |
| Santa Maria Valley Water Conservation District | Special District | Santa Maria | |
| Santa Ynez River Water Conservation District | Special District | Santa Ynez | |
| Santa Ynez River Water Conservation District Improvement District No. 1 | Special District | Santa Ynez | |
| Santiago County Water District | Special District | Orange | Orange |
| Saucelito Irrigation District | Special District | ||
| Scott Valley Irrigation District | Special District | Scotts Valley | Santa Cruz |
| Scotts Valley Water District | Special District | Scotts Valley | Santa Cruz |
| Semitropic Water Storage District | Special District | Wasco | Kern |
| Serrano Water District | Special District | Villa Park | Orange |
| Shafter-Wasco Irrigation District | Special District | Wasco | Kern |
| Shasta Community Services District | Special District | Shasta | Shasta |
| Shasta County Water Agency | Special District | Redding | Shasta |
| Sierra Cedars Community Services District | Special District | Shaver Lake | |
| Sierra Highlands Community Services District | Special District | Bishop | |
| Sierra Lakes County Water District | Special District | ||
| Skyline County Water District | Special District | Woodside | |
| Solano County Water Agency | Special District | Vacaville | Solano |
| Solano Irrigation District | Special District | Vacaville | Solano |
| Sonoma County Water Agency | Special District | Santa Rosa | Sonoma |
| Sonoma Mountain County Water District | Special District | Sonoma | |
| Soquel Creek Water District | Special District | Soquel | |
| South Coast WD | Special District | Laguna Beach | Orange |
| South Montebello Irrigation District | Special District | Montebello | LA |
| South San Joaquin Irrigation District | Special District | Manteca | San Joaquin |
| Water Agency | Type | Office | County |
| Alameda County Flood Control & Water Conservation District, Zone 7 | County & Spec. Dist. | Pleasanton | Alameda |
| Alameda County Water District | Special District | Fairmont | Alameda |
| Alpaugh Irrigation District | Special District | ||
| Alpine Springs County Water District | Special District | Tahoe City | |
| Alta Irrigation District | Special District | ||
| Amador County Department of Water Resources | Special District | Jackson | Amador |
| Amador Water Agency | Special District | Jackson | Amador |
| American River Flood Control District | Special District | Sacramento | |
| American States Water Company | NGO | ||
| American Water Works Service | NGO | National City | San Diego |
| Anaheim Water | City | Anaheim | Orange |
| Anderson-Cottonwood Irrigation District | Special District | ||
| Angiola Water District | Special District | ||
| Antelope Valley-East Kern Water Agency | Special District | Quartz Hill | LA-Kern |
| Apple Valley Foothill County Water District | Special District | Apple Valley | San Bernardino |
| Apple Valley Heights County Water District | Special District | Apple Valley | San Bernardino |
| Arcade Water District | Special District | Sacramento | |
| Armstrong Valley Water Company | NGO | Guerneville | |
| Aromas Water District | Special District | Aromas | Santa Clara |
| Arvin-Edison Water Storage District | Special District | Arvin | |
| Atascadero Mutual Water District | Special District | Atascadero | |
| Azurix | NGO | Los Angeles | Los Angeles |
| Azusa Light & Water | City | Azusa | LA |
| Baldy Mesa Water District | Special District | Victorville | LA |
| Banta-Carbona Irrigation District | Special District | ||
| Bard Water District | Special District | ||
| Bass Lake Water Company | NGO | Bass Lake | |
| Bear Valley Community Services District | Special District | Tehachapi | Kern |
| Bear Valley Water District | Special District | Redlands | San Bernardino |
| Beaumont-Cherry Valley Water District | Special District | Cherry Valley | Riverside |
| Bella Vista Water District | Special District | ||
| Belmont County Water District | Special District | Belmont | |
| Belridge Water Services District | Special District | Bakersfield | Kern |
| Belridge Water Storage District | Special District | ||
| Berrenda Mesa Water District | Special District | Bakersfield | Kern |
| Big Bear Area Regional Wastewater Agency | Special District | Big Bear City | San Bernardino |
| Big Bear City Community Services District | Special District | Big Bear City | San Bernardino |
| Big Bear Municipal Water District | Special District | Big Bear City | San Bernardino |
| Big Pine Community Service | Special District | Big Pine | |
| Biggs-West Gridley Water District | Special District | Gridley | |
| Bighorn-Desert View Water Agency | Special District | Landers | San Bernardino |
| Bodega Bay Public Utilities District | Special District | Bodega Bay | |
| Bolinas Community Public Utility District | Special District | ||
| Boron Community Services District | Special District | Boron | San Bernardino |
| Borrego Water District | Special District | Borrego Springs | San Diego |
| Bridgeport Public Utilities District | Special District | Bridgeport | |
| Broadview Water District | Special District | ||
| Brooktrails Township Community Services District | Special District | Willits | |
| Brophy Water District | Special District | Marysville | |
| Browns Valley Irrigation District | Special District | Browns Valley | |
| Buellton Community Services District | Special District | Buellton | |
| Buena Vista Water Storage District | Special District | Buttonwillow | |
| Bueno Colorado Municipal Water District | Special District | Vista | San Diego |
| Burney Water District | Special District | Burney | |
| Butte Water District | Special District | ||
| Byron-Bethany Irrigation District | Special District | Byron | |
| Cachuma Operation and Maintenance Board | Special District | ||
| Cachuma Operations & Maintenance | Special District | Santa Barbara | Santa Barbara |
| Cadiz Inc. | NGO | Los Angeles | LA |
| Calaveras County Water District | Special District | San Andreas | Calaveras |
| Calaveras Public Utilities District | Special District | San Andreas | Calaveras |
| California Avocado Commission | NGO | ||
| California Domestic Water Company | NGO | Whittier | LA |
| California Water Service Company | NGO | San Jose | Santa Clara |
| California-American Water Company | NGO | ||
| Calleguas Municipal Water District | Special District | Thousand Oaks | Ventura |
| Calpella County Water District | Special District | Calpella | |
| Cambria Community Services District | Special District | Cambria | |
| Camp Far West Irrigation District | Special District | ||
| Camrosa Water District | Special District | Camarillo | Ventura |
| Capistrano Beach Water District | Special District | Capistrano | Orange |
| Capistrano Valley Water District | Special District | San Juan Capistrano | Orange |
| Carlsbad MWD | Special District | Carlsbad | San Diego |
| Carmichael Water District | Special District | Carmichael | |
| Carminteria County Water District | Special District | Carpinteria | Santa Barbara |
| Carpenter Irrigation District | Special District | Orange | Orange |
| Carpinteria Valley Water District | Special District | Carpinteria | Santa Barbara |
| Casitas Municipal Water District | Special District | Oak View | |
| Castaic Lake Water Agency | Special District | Santa Clarita | LA |
| Castroville Water District | Special District | Castroville | |
| Cawelo Water District | Special District | Bakersfield | Kern |
| Centerville Community Services District | Special District | ||
| Central Basin MWD | Special District | Carson | LA |
| Central California Irrigation District | Special District | Los Banos | |
| Central Coast Water Authority | Special District | ||
| Central San Joaquin Water Conservation District | Special District | Stockton | |
| Central Water District | Special District | ||
| Channel Islands Beach Community Services District | Special District | Channel Island | Ventura |
| Chester Public Utilities District | Special District | Chester | |
| Chino Basin Water Conservation District | Special District | Chino | San Bernardino |
| Chino Basin Watermaster | Special District | San Bernardino | |
| Chowchilla Water District | Special District | ||
| Circle Oaks County Water District | Special District | ||
| Citrus Heights Water District | Special District | Citrus Heights | LA |
| City of Adelanto | City | Adelanto | San Bernardino |
| City of Alhambra | City | Alhambra | LA |
| City of Anderson | City | Anderson | |
| City of Arcata | City | Arcarta | |
| City of Bellflower | City | Bellflower | LA |
| City of Beverly Hills | City | Beverly Hills | LA |
| City of Brea | City | Brea | Orange |
| City of Brentwood Public Works | City | Brentwood | LA |
| City of Buellton | City | Buellton | |
| City of Buena Park | City | Buena Park | Orange |
| City of Camarillo | City | Camarillo | Ventura |
| City of Cotati | City | Cotati | |
| City of Escondido | City | Escondido | San Diego |
| City of Fairfield | City | Fairfield | |
| City of Fallbrook | City | Fallbrook | San Diego |
| City of Fresno Water Division | City | Fresno | Fresno |
| City of Hanford | City | Hanford | |
| City of Huntington Beach | City | Huntington Beach | Orange |
| City of Lakeport | City | Lakeport | |
| City of Lakewood | City | Lakewood | LA |
| City of Morgan Hill | City | Morgan Hill | Santa Clara |
| City of Norwalk | City | Norwalk | LA |
| City of Oceanside | City | Oceanside | San Diego |
| City of Palo Alto | City | Palo Alto | |
| City of Pittsburg | City | Pittsburg | |
| City of Pomona | City | Pomona | LA |
| City of Poway | City | Poway | San Diego |
| City of Redding Water Utility | City | Redding | |
| City of Riverside | City | Riverside | Riverside |
| City of Roseville | City | Roseville | |
| City of Running Springs | City | Running Springs | |
| City of Sacramento Utilities Department | City | Sacramento | Sacramento |
| City of San Bernardino Municipal Water Department | City | San Bernardino | San Bernardino |
| City of Santa Barbara | City | Santa Barbara | Santa Barbara |
| City of Santa Cruz Water Department | City | Santa Cruz | Santa Cruz |
| City of Santa Rosa | City | Santa Rosa | Santa Rosa |
| City of South Pasadena Water Department | City | S. Pasadena | LA |
| Clawa County Water District | Special District | Fresno | |
| Clear Creek Community Services District | Special District | ||
| Coachella Valley Water District | Special District | Coachella | Riverside |
| Coastside County Water District | Special District | Half Moon Bay | |
| Colusa Basin Drainage District | Special District | Arbuckle | |
| Colusa County Water District | Special District | Arbuckle | Colusa |
| Consolidated Irrigation District | Special District | ||
| Contra Costa County Water Agency | Special District | Martinez | Contra Costa |
| Contra Costa Water District | Special District | Concord | Contra Costa |
| Corcoran Irrigation District | Special District | Corcoran | |
| Cordua Irrigation District | Special District | Marysville | |
| Corning Water District | Special District | Corning | |
| Corona Water Utility | City | Corona | Riverside |
| Cottonwood Water District | Special District | Cottonwood | |
| County of Contra Costa | County | Martinez | Contra Costa |
| Covina Irrigating Company | NGO | Covina | LA |
| Crescenta Valley Water District | Special District | La Crescenta | LA |
| Crestline Sanitation District | Special District | Crestline | San Bernardino |
| Crestline Village Water District | Special District | Crestline | San Bernardino |
| Crestline-Lake Arrowhead Water Agency | Special District | Crestline | San Bernardino |
| Cucamonga County Water District | Special District | Rancho Cucamonga | San Bernardino |
| Cucamonga County WD | Special District | Rancho Cucamonga | San Bernardino |
| Deer Creek and Tule River Authority | Special District | ||
| Del Paso Manor Water District | Special District | Sacramento | |
| Del Puerto Water District | Special District | ||
| Delano-Earlimart Irrigation District | Special District | ||
| Delhi County Water District | Special District | ||
| Delta Diablo Sanitary District | Special District | ||
| Descanso Community Water District | Special District | Descanso | |
| Desert Water Agency | Special District | Palm Springs | Riverside |
| Devil's Den Water District | Special District | Santa Clarita | LA |
| Devore Mutual Water Company | NGO | Devore | |
| Diablo Water District | Special District | ||
| Donner Lake Utility Company | NGO | Truckee | |
| Dublin San Ramon Services District | Special District | Dublin | Alameda-Contra Costa |
| Ducor Community Services District | Special District | ||
| Dudley Ridge Water District | Special District | Fresno | |
| Dunnigan Water District | Special District | Dunnigan | |
| East Bay Municipal Utilities District | Special District | Oakland | Alameda |
| East Blythe County Water District | Special District | Blythe | |
| East Contra Costa Irrigation District | Special District | Brentwood | Contra Costa |
| East Niles Community Services District | Special District | Bakersfield | Kern |
| East Orange County Water District | Special District | Orange | Orange |
| East Pasadena Water Company | NGO | Pasadena | LA |
| East Valley Water District | Special District | San Bernardino | San Bernardino |
| Eastern Municipal Water District | Special District | Perris | Riverside |
| Eastside Water District | Special District | ||
| El Dorado County Water Agency | Special District | Placerville | El Dorado |
| El Dorado Irrigation District | Special District | El Dorado | |
| El Nido Irrigation District | Special District | El Nido | |
| El Toro Water District | Special District | Lake Forest | Orange |
| Elsinore Valley MWD | Special District | Elsinore | Riverside |
| Empire West Side Irrigation District | Special District | Stratford | |
| Encina Water Pollution Control Facility | Special District | ||
| Erskine Creek Water Company | NGO | Lake Isabella | |
| Escondido Water/Sewer | City | Escondido | San Diego |
| Exeter Irrigation District | Special District | ||
| Fair Oaks Water District | Special District | ||
| Fall River Mills Community Services District | Special District | Fall River | |
| Fallbrook Public Utilities District | Special District | Fallbrook | San Diego |
| Feather Water District | Special District | Yuba City | |
| Firebaugh Canal Water District | Special District | ||
| Foothill Municipal Water District | Special District | Flintridge | LA |
| Foresthill Public Utilities District | Special District | ||
| Forestville County Water District | Special District | Forestville | |
| Fountain Valley Public Works | City | Fountain Valley | Orange |
| Fox Canyon Groundwater Management Agency | Special District | Ventura | Ventura |
| Frazier Park Public Utilities District | Special District | ||
| Free Water County Water District | Special District | Sanger | |
| Fresno Irrigation District | Special District | Fresno | Fresno |
| Fresno Metropolitan Flood Control District | Special District | Fresno | Fresno |
| Friant Power Authority | Special District | ||
| Friant Water Users Authority | Special District | Lindsay | |
| Fruitridge Vista Water Company | NGO | Sacramento | |
| Fullerton Water | City | Fullerton | Orange |
| Garberville Water Company | NGO | Garberville | |
| Garden Grove DPW | City | Garden Grove | Orange |
| Georgetown Divide Public Utilities District | Special District | ||
| Glenn-Colusa Irrigation District | Special District | Willows | |
| Glide Water District | Special District | ||
| Golden Hills Community Services District | Special District | Tehachapi | Kern |
| Goleta Water District | Special District | Goleta | Santa Barbara |
| Graeagle Water Company | NGO | Graeagle | |
| Grassland Water District | Special District | Los Banos | |
| Gravelly Ford Water District | Special District | Madera | |
| Greenfield County Water District | Special District | Bakersfield | Kern |
| Heather Glen Community Services District | Special District | Applegate | |
| Heber Public Utility District | Special District | City | Imperial |
| Helix Water District | Special District | La Mesa | San Diego |
| Hesperia Water District | Special District | Hesperia | San Bernardino |
| Hetch Hetchy Water & Power | Special District | San Francisco- | |
| Hidden Valley Lake Community Services District | Special District | Middletown | |
| Hi-Desert Water District | Special District | Yucca Valley | San Bernardino |
| Highlands Water Company | NGO | Clearlake | |
| Hoopa Valley Public Utilities | Special District | Hoopa | |
| Humboldt Bay Municipal Water District | Special District | Humboldt | |
| Humboldt Community Services District | Special District | Cutten | Humboldt |
| Huntington Beach Water | City | Huntington Beach | Orange |
| Idyllwild Water District | Special District | San Bernardino | |
| Imperial ID | Special District | Imperial | Imperial |
| Imperial Irrigation District | Special District | Imperial | Imperial |
| Indian Wells Valley Water District | Special District | Ridgecrest | |
| Inland Empire Utilities Agency | Special District | Rancho Cucamonga | San Bernardino |
| Inyo County Water Department | County | Bishop | |
| Irvine Ranch Water District | Special District | Irvine | Orange |
| Ivanhoe Irrigation District | Special District | Visalia | |
| Ivanhoe Public Utilities District | Special District | Ivanhoe | |
| James Irrigation District | Special District | San Joaquin | |
| Joshua Basin Water District | Special District | ||
| June Lake Public Utilities District | Special District | ||
| Jurupa Community Services District | Special District | Riverside | Riverside |
| Kanawha Water District | Special District | ||
| Kaweah Delta Water Conservation District | Special District | ||
| Kaweah River Power Authority | Special District | Tulare | |
| Kern County Water Agency | Special District | Bakersfield | Kern |
| Kern Delta Water District | Special District | Kern | |
| Kern Water Bank Authority | Special District | Bakersfield | Kern |
| Kern-Tulare Water District | Special District | Kern-Tulare | |
| Keswick Community Services | Special District | Shasta | |
| Kings County Water District | Special District | Hanford | Kings |
| Kings River Conservation District | Special District | Fresno | Kings |
| Kings River Water District | Special District | Sanger | |
| Kinneloa Irrigation District | Special District | ||
| Kirkwood Meadows Public Utilities District | Special District | Kirkwood | |
| Knights Landing Ridge Drainage District | Special District | ||
| La Canada Irrigation District | Special District | La Canada Flintridge | LA |
| LA City Bureau of Sanitation | City | LA | LA |
| LA County San Districts | Special District | Whittier | LA |
| La Habra Heights County Water District | Special District | La Habra Hts | Orange |
| La Puente Valley County Water District | Special District | LA | |
| LA Stormwater Program | |||
| LADWP | City | LA | LA |
| LADWP Water | City | LA | LA |
| Laguna Beach County Water District | Special District | Laguna Beach | Orange |
| Laguna Beach Ocean Water | Special District | Laguna Beach | Orange |
| Laguna Irrigation District | Special District | Riverdale | |
| Laguna Niguel Public Works | City | Laguna Niguel | Orange |
| Lake Arrowhead Community Services District | Special District | Lake Arrowhead | San Bernardino |
| Lake County Flood Control & Water Conservation District | Special District | ||
| Lake Forest Public Works | City | Lake Forest | Orange |
| Lake Hemet Municipal Water District | Special District | Hemet | Riverside |
| Lake Shastina Mutual Water District | Special District | Weed | |
| Lakeside Irrigation Water District | Special District | ||
| Lakeside Water District | Special District | ||
| Las Flores Water Company | NGO | Altadena | LA |
| Las Virgenes MWD | Special District | Calabasas | LA |
| Laton Community Services District | Special District | ||
| Laytonville County Water District | Special District | Laytonville | |
| Le Grand Community Services District | Special District | ||
| Le Grand-Athlone Water District | Special District | ||
| Leucadia County WD | Special District | Leucadia | San Diego |
| Linda County Water District | Special District | Marysville | |
| Linden County Water District | Special District | Linden | |
| Lindmore Irrigation District | Special District | ||
| Lindsay-Strathmore Irrigation District | Special District | ||
| Littlerock Creek Irrigation District | Special District | Littlerock | |
| Long Beach Water | City | Long Beach | LA |
| Los Alamos Community Services District | Special District | ||
| Los Alisos Water District | Special District | Lake Forest | Orange |
| Los Angeles County Waterworks Districts | Special District | LA | LA |
| Los Angeles Department of Water and Power | Special District | LA | LA |
| Lost Hills Water District | Special District | Bakersfield | Kern |
| Lower San Joaquin Levee District | Special District | Dos Palos | |
| Lower Tule River Irrigation District | Special District | Woodville | |
| Madera Irrigation District | Special District | Madera | Madera |
| Madera Water District | Special District | Madera | Madera |
| Madera-Chowchilla Power Authority | Special District | Madera | Madera |
| Main San Gabriel Basin Watermaster | Special District | Azusa | LA |
| Maine Prairie Water District | Special District | ||
| Majestic Pines Community Services District | Special District | San Diego | San Diego |
| Malaga County Water District | Special District | Fresno | Fresno |
| Mammoth Community Water District | Special District | ||
| Mammoth County Water District | Special District | Mammoth | |
| Mariana Ranchos County Water District | Special District | Apple Valley | San Bernardino |
| Marin Municipal Water District | Special District | Corte Madera | Marin |
| Marina Coast Water District | Special District | Marina | |
| Mariposa County Water District | Special District | Mariposa | |
| Mariposa Public Utilities District | Special District | Mariposa | |
| Mariposa Public Utility District | Special District | Mariposa | |
| Marygold Mutual Water | Special District | Bloomington | |
| Maxwell Irrigation District | Special District | ||
| Maywood Mutual Water Company | NGO | Maywood | |
| McCloud Community Services | Special District | McCloud | |
| Meadow Vista County Water District | Special District | Meadow Vista | |
| Mendocino County Water Agency | Special District | Mendocino | |
| Merced Irrigation District | Special District | Merced | |
| Mesa Consolidated Water District | Special District | Costa Mesa | Orange |
| Metropolitan Water District of Southern California | Special District | LA | Coastal SoCal |
| Midway Heights County Water District | Special District | Midway | |
| Mil Potrero Mutual Water Company | NGO | Frazier Park | |
| Millview County Water District | Special District | Ukiah | |
| Mission Hills Community Services District | Special District | Lompoc | Santa Barbara |
| Mission Springs Water District | Special District | Desert Hot Springs | San Bernardino |
| Modesto Irrigation District | Special District | Modesto | |
| Mojave Public Utilities District | Special District | Mojave | San Bernardino |
| Mojave Water Agency | Special District | Apple Valley | San Bernardino |
| Montague Water Conservation District | Special District | Montague | |
| Monte Vista Water District | Special District | Montclair | San Bernardino |
| Montebello Land & Waer Company | NGO | Montebello | LA |
| Montecito Sanitary District | Special District | Santa Barbara | Santa Barbara |
| Montecito Water District | Special District | Santa Barbara | Santa Barbara |
| Monterey County Public Works-Community Service Area #75 | Special District | Salinas | Monterey |
| Monterey County Water Resources Agency | Special District | Salinas | Monterey |
| Monterey Peninsula Water Management District | Special District | Salinas | Monterey |
| Moulton Niguel WD | Special District | Laguna Niguel | Orange |
| Mountain Gate Community Services District | Special District | ||
| Municipal Water District of Orange County | Special District | Fountain Valley | Orange |
| Murrieta County Water District | Special District | Murrieta | |
| Nevada Irrigation District | Special District | ||
| Newhall County Water District | Special District | Newhall | LA |
| Newport Beach Public Works | City | Newport Beach | Orange |
| North Coast County Water District | Special District | Pacifica | |
| North Delta Water Agency | Special District | Sacramento | |
| North Kern Water Storage District | Special District | Bakersfield | Kern |
| North Marin Water District | Special District | Novato | Marin |
| North of the River Municipal Water District | Special District | Bakersfield | Kern |
| North San Joaquin Water Conservation District | Special District | Lodi | San Joaquin |
| Northridge Water District | Special District | Sacramento | Sacramento |
| Oakdale Irrigation District | Special District | ||
| Oceanside Water Utilities | City | Oceanside | San Diego |
| Oildale Mutual Water Company | NGO | Bakersfield | Kern |
| Ojai Basin Groundwater Management Agency | Special District | Ojai | Ventura |
| Olcese Water District | Special District | Bakersfield | Kern |
| Olivenhain MWD | Special District | Encinitas | San Diego |
| Omochumne-Hartnell Water District | Special District | Wilton | |
| Orange County Sanitation District | Special District | Fountain Valley | Orange |
| Orange County Water District | Special District | Fountain Valley | Orange |
| Orange Cove Irrigation District | Special District | ||
| Orange Public Works | City | Orange | Orange |
| Orchard Dale Water District | Special District | Whittier | LA |
| Orland-Artois Water District | Special District | Orland | |
| Orosi Public Utilities District | Special District | Orosi | |
| Oroville-Wyandotte Irrigation District | Special District | Oroville | |
| Otay Water District | Special District | Spring Valley | San Diego |
| Pacheco Water District | Special District | ||
| Padre Dam MWD | Special District | ||
| Pajaro Valley Water Management Agency | Special District | ||
| Pajaro/Sunny Mesa Community Services District | Special District | Watsonville | |
| Palm Ranch Irrigation District | Special District | Quartz Hill | |
| Palmdale Water District | Special District | Palmdale | LA |
| Palo Verde Irrigation District | Special District | ||
| Panoche Drainage District | Special District | Firebaugh | |
| Panoche Water District | Special District | Firebaugh | |
| Paradise Irrigation District | Special District | Paradise | |
| Park Water Co. | NGO | Downey | LA |
| Pasadena W&P | City | Pasadena | LA |
| Patterson Water District | Special District | ||
| Pebble Beach Community Services District | Special District | ||
| Pescadero Reclamation District #2058 | Special District | Tracy | |
| Pico Water District | Special District | Pico Rivera | LA |
| Pinedale County Water District | Special District | Pinedale | |
| Pinyon Pines County Water District | Special District | Mountain | |
| Pixley Irrigation District | Special District | Pixley | |
| Placer County Water Agency | Special District | Auburn | Placer |
| Plain View Water District | Special District | ||
| Planada Community Services District | Special District | Planada | |
| Pleasant Valley County Water District | Special District | Camarillo | Ventura |
| Pleasant Valley Water District | Special District | Coalinga | |
| Pomona-Walnut-Rowland Joint Water Line Commission | Special District | Pomona | LA |
| Port Hueneme Water Agency | Special District | Ventura | |
| Porterville Irrigation District | Special District | Porterville | |
| Poseidon Resources, Inc. | NGO | Long Beach | LA |
| Princeton-Codora-Glenn Irrigation District | Special District | ||
| Provident Irrigation District | Special District | ||
| Purissima Hills Water District | Special District | Los Altos Hills | |
| Quartz Hill Water District | Special District | ||
| Rag Gulch Water District | Special District | ||
| Rainbow MWD | Special District | Fallbrook | San Diego |
| Raisin City Water District | Special District | Raisin City | |
| Ramirez Water District | Special District | Marysville | |
| Ramona Municipal Water District | Special District | Ramona | San Diego |
| Rancho California Water District | Special District | Temecula | Riverside |
| Rand Communities Water District | Special District | Randsberg | |
| Reclamation District No. 2068 | Special District | Dixon | |
| Reclamation District No. 999 | Special District | Clarksburg | |
| Redwood Valley County Water District | Special District | Redwood Valley | |
| Richvale Irrigation District | Special District | Richvale | |
| Rincon del Diablo Municipal Water District | Special District | Escondido | San Diego |
| Rio Alto Water District | Special District | Cottonwood | |
| Rio Linda-Elverta Community Water District | Special District | ||
| Riverdale Irrigation District | Special District | Riverdale | |
| Riverside Public Utilities | City | Riverside | Riverside |
| Riverview Water District | Special District | Lakeside | |
| Rogina Water Company | NGO | Talmage | |
| Root Creek Water District | Special District | ||
| Rosamond Community Services District | Special District | ||
| Rosedale-Rio Bravo Water Storage District | Special District | ||
| Rowland Water District | Special District | Rowland Hts | LA |
| Rubio Canyon Land & Water Co. | NGO | Altadena | LA |
| Sacramento County Water Maintenance District | County | Sacramento | Sacramento |
| Sacramento Metropolitan Water Authority | Special District | Sacramento | Sacramento |
| Sacramento River West Side Levee District | Special District | Grimes | Sacramento |
| San Andreas Sanitary District | Special District | ||
| San Benito County Water District | Special District | Laguna Hills | Orange |
| San Benito County Water District | Special District | Hollister | San Benito |
| San Bernardino Valley Municipal Water District | Special District | San Bernardino | San Bernardino |
| San Bernardino Valley Water Conservation District | Special District | Redlands | San Bernardino |
| San Clemente Utilities | City | San Clemente | Orange |
| San Diego County Water Authority | Special District | San Diego | San Diego |
| San Diego Metro Waste- | City | San Diego | San Diego |
| San Diego Water Dep't | City | San Diego | San Diego |
| San Dieguito Water District | Special District | Encinitas | San Diego |
| San Francisco Public Utilities Commission | City | San Francisco | San Francisco |
| San Gabriel Basin Water Quality Authority | Special District | Covina | LA |
| San Gabriel County Water District | Special District | LA | |
| San Gabriel Valley Municipal Water District | Special District | Azusa | LA |
| San Gorgonio Pass Water Agency | Special District | LA | |
| San Joaquin County Flood Control & Water Conservation District | Special District | Stockton | San Joaquin |
| San Joaquin River Exchange Contractors Water Authority | Special District | Los Banos | |
| San Juan Basin Authority | Special District | San Juan Capistrano | Orange |
| San Juan Capistrano Public Works | |||
| San Juan Ridge County Water District | Special District | ||
| San Juan Water District | Special District | Granite Bay | |
| San Juan WD | |||
| San Lorenzo Valley County Water District | Boulder Creek | ||
| San Luis & Delta-Mendota Water Authority | Special District | ||
| San Luis Water District | Special District | Los Banos | |
| Santa Ana Mountain County Water District | Special District | Trabuco | Orange |
| Santa Ana Public Works | City | Santa Ana | Orange |
| Santa Ana Watershed Project Authority | Special District | Riverside | Orange-Riverside-San Bernardino |
| Santa Carbona Irrigation District | Special District | Tracy | |
| Santa Clara Valley Water District | Special District | San Jose | Santa Clara |
| Santa Clarita Water Company | NGO | Saugus | LA |
| Santa Fe Irrigation District | Special District | Rancho Santa Fe | |
| Santa Margarita WD | Special District | Las Flores | Orange |
| Santa Maria Valley Water Conservation District | Special District | Santa Maria | |
| Santa Ynez River Water Conservation District | Special District | Santa Ynez | |
| Santa Ynez River Water Conservation District Improvement District No. 1 | Special District | Santa Ynez | |
| Santiago County Water District | Special District | Orange | Orange |
| Saucelito Irrigation District | Special District | ||
| Scott Valley Irrigation District | Special District | Scotts Valley | Santa Cruz |
| Scotts Valley Water District | Special District | Scotts Valley | Santa Cruz |
| Semitropic Water Storage District | Special District | Wasco | Kern |
| Serrano Water District | Special District | Villa Park | Orange |
| Shafter-Wasco Irrigation District | Special District | Wasco | Kern |
| Shasta Community Services District | Special District | Shasta | Shasta |
| Shasta County Water Agency | Special District | Redding | Shasta |
| Sierra Cedars Community Services District | Special District | Shaver Lake | |
| Sierra Highlands Community Services District | Special District | Bishop | |
| Sierra Lakes County Water District | Special District | ||
| Skyline County Water District | Special District | Woodside | |
| Solano County Water Agency | Special District | Vacaville | Solano |
| Solano Irrigation District | Special District | Vacaville | Solano |
| Sonoma County Water Agency | Special District | Santa Rosa | Sonoma |
| Sonoma Mountain County Water District | Special District | Sonoma | |
| Soquel Creek Water District | Special District | Soquel | |
| South Coast WD | Special District | Laguna Beach | Orange |
| South Montebello Irrigation District | Special District | Montebello | LA |
| South San Joaquin Irrigation District | Special District | Manteca | San Joaquin |
| South Sutter Water District | Special District | Trowbridge | |
| South Tahoe Public Utilities District | Special District | South Lake Tahoe | |
| South Yuba Water District | Special District | Sacramento | Sacramento |
| Southern California Water Company | NGO | Several | SoCal Area |
| Southern San Joaquin Municipal Utilities District | Special District | ||
| Southwest Water Company | NGO | ||
| Springville Public Utilities District | Special District | ||
| Squaw Valley County Water District | Special District | Olympic Valley | |
| St. Johns Water District | Special District | Visalia | |
| Stinson Beach County Water District | Special District | Stinson Beach | |
| Stockton East Water District | Special District | Stockton | |
| Stone Corral Irrigation District | Special District | Visalia | |
| Strathmore Public Utility District | Special District | Strathmore | |
| Suisun Solano Water Agency | Special District | ||
| Summerland County Water District | Special District | Summerland | |
| Sunnymead Mutual Water Company | NGO | Sunnymead | |
| Sunnyslope County Water District | Special District | Hollister | San Benito |
| Sutter Extension Water District | Special District | Yuba City | |
| Sweetwater Authority | Special District | San Diego | |
| Sweetwater Springs WD | Special District | San Diego | |
| Tahoe City Public Utilities District | Special District | ||
| Tea Pot Dome Water District | Special District | Porterville | |
| Tehachapi-Cummings County Water District | Special District | ||
| Tehama County Flood Control & Water Conservation District | Special District | Tehama | |
| Tehama-Colusa Canal Authority | Special District | Tehama-Colusa | |
| Temescal Water Company | NGO | Corona | Riverside |
| Templeton Community Services District | Special District | Templeton | |
| Terra Bella Irrigation District | Special District | ||
| The West Side Irrigation District | Special District | Tracy | |
| Thermalito Irrigation District | Special District | Oroville | |
| Three Valleys Municipal Water District | Special District | Claremont | LA |
| Thunderbird County Water District | Special District | Apple Valley | San Bernardino |
| Torrance Municipal WD | City | Torrance | LA |
| Town of Los Gatos | Town | Los Gatos | |
| Trabuco Canyon Water District | Special District | Trabuco | Orange |
| Tranquillity Irrigation District | Special District | Tranquility | |
| Tri-Cities Municipal Water District | Special District | San Clemente | Orange |
| Tri-Valley Water District | Special District | ||
| Truckee Donner Public Utilities District | Special District | Truckee | |
| Tulare County Water Works #1 | Special District | Tulare | Tulare |
| Tulare Irrigation District | Special District | Tulare | Tulare |
| Tulare Lake Basin Water Storage District | Special District | ||
| Tulelake Irrigation District | Special District | ||
| Tuolumne Utilities District | Special District | Sonora | |
| Turlock Irrigation District | Special District | ||
| Tustin Water | City | Tustin | Orange |
| Twentynine Palms Water District | Special District | Twentnine Palms | San Bernardino |
| United Water Conservation District | Special District | Santa Paula | Ventura |
| Upper Lake County Water District | Special District | Upper Lake | |
| Upper San Gabriel Valley Municipal Water District | Special District | El Monte | LA |
| Utica Power Authority | Special District | ||
| Vallecitos Water District | Special District | San Marcos | San Diego |
| Valley Center Municipal Water District | Special District | Valley Center | |
| Valley County Water District | Special District | Baldwin Park | LA |
| Valley of the Moon Water District | Special District | El Verano | Sonoma |
| Valley Water Company | NGO | La Canada | LA |
| Vandenberg Village Community Services District | Special District | ||
| Ventura County Public Works Water Resources | County | Ventura | Ventura |
| Ventura County PW Water and Sanitation | County | Ventura | Ventura |
| Ventura River County Water District | Special District | Ventura | Ventura |
| Ventural County Waterworks | County | Moorpark | Ventura |
| Victor Valley Water District | Special District | Victorville | San Bernardino |
| Vista Irrigation District | Special District | Vista | San Diego |
| W.H. Wilbur Reclamation District #825 | Special District | ||
| Walnut Valley Water District | Special District | Walnut | LA |
| Water Replenishment District of Southern California | Special District | Cerritos | LA |
| Weaverville Community Services District | Special District | ||
| Weott Community Services District | Special District | ||
| West Basin MWD | Special District | Carson | LA |
| West Kern Water District | Special District | Kern | |
| West San Bernardino County Water District | Special District | Rialto | San Bernardino |
| West Stanislaus Irrigation District | Special District | ||
| Westborough Water District | Special District | S. San Francisco | |
| Western Canal Water District | Special District | Richvale | |
| Western Municipal Water District | Special District | Riverside | Riverside |
| Westlands WD | Special District | Fresno | |
| Westside Water District | Special District | Williams | |
| Wheeler Ridge-Maricopa Water Storage District | Special District | Bakersfield | Kern |
| Windsor Water District | Special District | Windsor | |
| Winton Water and Sanitation | City | Winton | |
| Woodbridge Irrigation District | Special District | Woodbridge | |
| Wynola Water District | Special District | Santa Ysabel | |
| Yolo County Flood Control & Water Conservation District | Special District | Yolo | |
| Yorba Linda Public Works | City | Yorba Linda | Orange |
| Yorba Linda WD | Special District | Yorba Linda | Orange |
| Yuba County Water Agency | Special District | Marysville | Yuba |
| Yuba County Water District | Special District | Brownsville | Yuba |
| Yucaipa Valley WD | Special District | Yucaipa | Riverside |
| Yuima Municipal Water District | Special District | ||
| Zone 7 Flood Control | County & Spec. Dist | Pleasanton | Alameda |
| Zone 7 Water Agency | County & Spec. Dist | Pleasanton | Alameda |