California Tap Water Quality: Is It Safe to Drink?

2026 EPA water quality data for 2,781 community water systems serving a combined 43,979,302 people in California. Find your water system to see violations, PFAS results, lead testing, and a safety grade — free.

California has the most community water systems of any state, ranging from massive urban utilities to tiny rural districts in the Central Valley. Groundwater contamination from nitrates, arsenic, and hexavalent chromium (chromium-6) affects many agricultural communities. The state has adopted some of the nation's strictest water quality standards, including its own notification level for chromium-6.

Find Your Water System in California

Enter your ZIP code to see EPA violations, lead test results, PFAS data, and a safety grade for your water.

📊 Data from EPA’s SDWIS · 🔄 Updated quarterly · 🏛️ 2,781 water systems in California

Showing the 250 largest of 2,781 community water systems in California, by population served. Use the ZIP search above or the city links to find a smaller system.

LOS ANGELES-CITY, DEPT. OF WATER & POWER LOS ANGELES, CA · 7,751,132 people · Surface Water EAST BAY MUD OAKLAND, CA · 1,442,800 people · Surface Water SAN DIEGO, CITY OF SAN DIEGO, CA · 1,385,379 people · Surface Water SAN JOSE WATER SAN JOSE, CA · 1,039,920 people · Surface Water SFPUC CITY DISTRIBUTION DIVISION BURLINGAME, CA · 848,019 people · Surface Water Purchased EASTERN MUNICIPAL WD PERRIS, CA · 666,581 people · Surface Water Purchased CITY OF FRESNO FRESNO, CA · 545,716 people · Surface Water CITY OF SACRAMENTO MAIN SACRAMENTO, CA · 527,979 people · Surface Water LONG BEACH UTILITIES DEPARTMENT LONG BEACH, CA · 466,772 people · Surface Water Purchased IRVINE RANCH WATER DISTRICT IRVINE, CA · 444,800 people · Surface Water CITY OF ANAHEIM ANAHEIM, CA · 348,593 people · Surface Water ALAMEDA COUNTY WATER DISTRICT FREMONT, CA · 344,000 people · Surface Water CITY OF SANTA ANA SANTA ANA, CA · 310,539 people · Surface Water Purchased RIVERSIDE, CITY OF RIVERSIDE, CA · 298,398 people · GWUDI SANTA CLARITA VALLEY WATER AGENCY NEWHALL, CA · 294,090 people · Surface Water GSWC - SOUTHWEST HAWTHORNE, CA · 277,740 people · Surface Water Purchased HELIX WATER DISTRICT LA MESA, CA · 277,668 people · Surface Water COACHELLA VWD: COVE COMMUNITY PALM DESERT, CA · 270,000 people · Groundwater CWS - BAKERSFIELD SAN JOSE, CA · 267,881 people · Surface Water SAN GABRIEL VALLEY WATER CO.-EL MONTE EL MONTE, CA · 248,000 people · Groundwater OTAY WATER DISTRICT SPRING VALLEY, CA · 238,008 people · Surface Water Purchased SAN GABRIEL VALLEY WC - FONTANA FONTANA, CA · 237,700 people · Surface Water MODESTO, CITY OF MODESTO, CA · 218,771 people · Surface Water Purchased SAN BERNARDINO CITY SAN BERNARDINO, CA · 214,665 people · Groundwater CUCAMONGA VALLEY WATER DISTRICT RANCHO CUCAMONGA, CA · 211,069 people · Surface Water LOS ANGELES CWWD 40 REG 4 & 34 LANCASTER ALHAMBRA, CA · 208,129 people · Surface Water Purchased CITY OF HUNTINGTON BEACH HUNTINGTON BEACH, CA · 201,000 people · Surface Water Purchased OXNARD WATER DEPT OXNARD, CA · 200,232 people · Surface Water Purchased CONTRA COSTA WATER DISTRICT CONCORD, CA · 198,000 people · Surface Water SACRAMENTO SUBURBAN WATER DISTRICT SACRAMENTO, CA · 194,444 people · Surface Water Purchased CITY OF STOCKTON STOCKTON, CA · 191,302 people · Surface Water SWEETWATER AUTHORITY CHULA VISTA, CA · 191,282 people · Surface Water GLENDALE-CITY, WATER DEPT. GLENDALE, CA · 188,784 people · Surface Water Purchased MARIN MUNICIPAL WATER DISTRICT CORTE MADERA, CA · 186,895 people · Surface Water ONTARIO MUNICIPAL UTILITIES COMPANY ONTARIO, CA · 185,010 people · Surface Water Purchased SCWA - LAGUNA/VINEYARD SACRAMENTO, CA · 184,896 people · Surface Water CALIFORNIA WATER SERVICE - STOCKTON SAN JOSE, CA · 176,266 people · Surface Water Purchased SANTA ROSA, CITY OF SANTA ROSA, CA · 175,396 people · Groundwater CITY OF GARDEN GROVE GARDEN GROVE, CA · 174,226 people · Surface Water Purchased OCEANSIDE, CITY OF OCEANSIDE, CA · 171,483 people · Surface Water Purchased MOULTON NIGUEL WATER DISTRICT LAGUNA HILLS, CA · 170,236 people · Surface Water Purchased ELSINORE VALLEY MWD LAKE ELSINORE, CA · 169,455 people · Surface Water SUBURBAN WATER SYSTEMS-SAN JOSE COVINA, CA · 168,843 people · Surface Water Purchased CORONA, CITY OF CORONA, CA · 168,575 people · Surface Water Purchased SANTA MARGARITA WATER DISTRICT RANCHO SANTA MARGARITA, CA · 168,289 people · Surface Water Purchased PASADENA WATER AND POWER PASADENA, CA · 164,344 people · Surface Water Purchased CITY OF HAYWARD HAYWARD, CA · 162,954 people · Surface Water Purchased BAKERSFIELD, CITY OF SAN JOSE, CA · 160,144 people · Surface Water Purchased CITY OF SUNNYVALE SUNNYVALE, CA · 157,566 people · Surface Water Purchased CITY OF ROSEVILLE ROSEVILLE, CA · 155,612 people · Surface Water CALIFORNIA WATER SERVICE CO. - ELA SAN JOSE, CA · 152,474 people · Surface Water Purchased POMONA - CITY, WATER DEPT. POMONA, CA · 151,713 people · Surface Water CWS - VISALIA SAN JOSE, CA · 148,496 people · Groundwater RANCHO CALIFORNIA WATER DISTRICT TEMECULA, CA · 146,147 people · Surface Water Purchased CALIFORNIA WATER SERVICE CO. - DOMINGUEZ SAN JOSE, CA · 143,996 people · Surface Water Purchased CITY OF FULLERTON FULLERTON, CA · 139,461 people · Surface Water Purchased ESCONDIDO, CITY OF ESCONDIDO, CA · 137,044 people · Surface Water VICTORVILLE WATER DISTRICT VICTORVILLE, CA · 135,983 people · Surface Water Purchased JURUPA COMMUNITY SD JURUPA VALLEY, CA · 135,093 people · Surface Water Purchased VISTA IRRIGATION DISTRICT VISTA, CA · 132,430 people · Surface Water EL DORADO ID - MAIN PLACERVILLE, CA · 132,171 people · Surface Water CITY OF SANTA CLARA SANTA CLARA, CA · 130,746 people · Surface Water Purchased CITY OF CLOVIS CLOVIS, CA · 130,130 people · Surface Water PALMDALE WATER DIST. PALMDALE, CA · 126,804 people · Surface Water CWSC SALINAS SAN JOSE, CA · 123,679 people · Groundwater CITY OF VALLEJO VALLEJO, CA · 121,420 people · Surface Water CITY OF ORANGE ORANGE, CA · 120,770 people · Surface Water Purchased CITY OF FAIRFIELD FAIRFIELD, CA · 120,377 people · Surface Water CITY OF ANTIOCH ANTIOCH, CA · 115,074 people · Surface Water CAL-WATER SERVICE CO.-CHICO SAN JOSE, CA · 114,925 people · Groundwater GOLDEN STATE WC - WEST ORANGE COUNTY ANAHEIM, CA · 114,379 people · Surface Water Purchased VALLECITOS WD SAN MARCOS, CA · 113,500 people · Surface Water Purchased VENTURA WATER DEPARTMENT VENTURA, CA · 113,500 people · Surface Water DOWNEY - CITY, WATER DEPT. DOWNEY, CA · 110,556 people · Groundwater GREAT OAKS WC INC SAN JOSE, CA · 110,088 people · Groundwater AZUSA LIGHT AND WATER AZUSA, CA · 110,044 people · Surface Water MESA WATER DISTRICT COSTA MESA, CA · 110,000 people · Surface Water Purchased SAN BERNARDINO VALLEY WD SAN BERNARDINO, CA · 109,608 people · Groundwater CITY OF SANTA MARIA UTILITIES DEPARTMENT SANTA MARIA, CA · 109,477 people · Surface Water Purchased EAST VALLEY WATER DISTRICT HIGHLAND, CA · 108,629 people · Surface Water TORRANCE-CITY, WATER DEPT. TORRANCE, CA · 106,183 people · Surface Water Purchased CAL-AM WATER CORONADO IMPERIAL BEACH, CA · 106,000 people · Surface Water Purchased BURBANK-CITY, WATER DEPT. BURBANK, CA · 105,603 people · Surface Water Purchased CITY OF DALY CITY DALY CITY, CA · 104,901 people · Surface Water Purchased WEST VALLEY WATER DISTRICT RIALTO, CA · 104,498 people · Surface Water CALIFORNIA WATER SERVICE - SAN MATEO SAN JOSE, CA · 102,348 people · Surface Water Purchased CITY OF SAN JOSE - EVG/EDV/COY SAN JOSE, CA · 101,265 people · Surface Water Purchased WALNUT VALLEY WATER DISTRICT WALNUT, CA · 100,941 people · Surface Water Purchased HESPERIA WD HESPERIA, CA · 100,744 people · Groundwater SOUTH TAHOE PUD - MAIN SOUTH LAKE TAHOE, CA · 100,000 people · Groundwater CITY OF VACAVILLE ELMIRA, CA · 99,650 people · Surface Water CITY OF SANTA BARBARA WATER DEPARTMENT SANTA BARBARA, CA · 99,323 people · Surface Water DUBLIN SAN RAMON SERVICES DISTRICT PLEASANTON, CA · 98,776 people · Surface Water Purchased CALIFORNIA WATER SERVICE CO. - HERM/REDO SAN JOSE, CA · 96,853 people · Surface Water Purchased TRACY, CITY OF TRACY, CA · 96,609 people · Surface Water CARLSBAD MWD CARLSBAD, CA · 95,158 people · Surface Water Purchased VENTURA WWD NO. 8 - SIMI VALLEY SIMI VALLEY, CA · 94,738 people · Surface Water Purchased SANTA CRUZ WATER DEPARTMENT SANTA CRUZ, CA · 94,626 people · Surface Water PADRE DAM MWD SANTEE, CA · 93,980 people · Surface Water Purchased CITY OF MERCED MERCED, CA · 93,692 people · Groundwater CITY OF REDWOOD CITY REDWOOD CITY, CA · 92,819 people · Surface Water Purchased CAL AM WATER COMPANY - MONTEREY PACIFIC GROVE, CA · 92,450 people · GWUDI CITY OF WESTMINSTER WESTMINSTER, CA · 90,911 people · Surface Water Purchased SANTA MONICA-CITY, WATER DIVISION LOS ANGELES, CA · 89,947 people · Surface Water Purchased CITY OF REDDING REDDING, CA · 89,628 people · Surface Water PLACER CWA - FOOTHILL AUBURN, CA · 89,544 people · Surface Water OLIVENHAIN MWD ENCINITAS, CA · 86,458 people · Surface Water Purchased CHINO, CITY OF CHINO, CA · 86,435 people · Surface Water Purchased WESTERN MWD RIVERSIDE, CA · 86,062 people · Surface Water Purchased MANTECA, CITY OF MANTECA, CA · 84,928 people · Surface Water Purchased NAPA, CITY OF NAPA, CA · 84,804 people · Surface Water INDIO WATER AUTHORITY INDIO, CA · 84,757 people · Groundwater GOLETA WATER DISTRICT GOLETA, CA · 84,462 people · Surface Water YORBA LINDA WATER DISTRICT PLACENTIA, CA · 84,292 people · Surface Water Purchased CITY OF BUENA PARK BUENA PARK, CA · 81,998 people · Surface Water Purchased CITY OF MILPITAS MILPITAS, CA · 81,773 people · Surface Water Purchased CITY OF MOUNTAIN VIEW MOUNTAIN VIEW, CA · 81,501 people · Surface Water Purchased FOLSOM, CITY OF - MAIN FOLSOM, CA · 80,969 people · Surface Water INGLEWOOD- CITY, WATER DEPT. INGLEWOOD, CA · 80,824 people · Surface Water Purchased CITY OF ALHAMBRA ALHAMBRA, CA · 79,776 people · Surface Water Purchased UPLAND, CITY OF UPLAND, CA · 78,376 people · Surface Water REDLANDS CITY MUD-WATER DIV REDLANDS, CA · 78,025 people · Surface Water CITY OF PLEASANTON PLEASANTON, CA · 76,689 people · Surface Water Purchased SOUTH GATE-CITY, WATER DEPT. SOUTH GATE, CA · 76,443 people · Surface Water Purchased CHINO HILLS, CITY OF CHINO HILLS, CA · 76,414 people · Surface Water Purchased COMPTON-CITY, WATER DEPT. COMPTON, CA · 74,877 people · Surface Water Purchased DESERT WATER AGENCY PALM SPRINGS, CA · 74,807 people · Surface Water TURLOCK, CITY OF TURLOCK, CA · 72,682 people · Surface Water Purchased LIBERTY UTILITIES - BELLFLOWER-NORWALK DOWNEY, CA · 72,624 people · Surface Water Purchased LAS VIRGENES MWD CALABASAS, CA · 72,602 people · Surface Water TULARE, CITY OF TULARE, CA · 72,241 people · Groundwater CALIFORNIA WATER SERVICE CO. - PALOS VER SAN JOSE, CA · 71,452 people · Surface Water Purchased CITY OF YUBA CITY YUBA CITY, CA · 70,256 people · Surface Water CWSC LOS ALTOS SUBURBAN SAN JOSE, CA · 69,973 people · Surface Water Purchased VALLEY COUNTY WATER DIST. BALDWIN PARK, CA · 68,871 people · Groundwater CITY OF NEWPORT BEACH NEWPORT BEACH, CA · 68,572 people · Surface Water Purchased LODI, CITY OF LODI, CA · 68,272 people · Surface Water CITRUS HEIGHTS WATER DISTRICT CITRUS HEIGHTS, CA · 67,818 people · Surface Water Purchased CITY OF DAVIS DAVIS, CA · 67,457 people · Surface Water Purchased CITY OF PALO ALTO PALO ALTO, CA · 67,231 people · Surface Water Purchased LYNWOOD-CITY, WATER DEPT. LYNWOOD, CA · 66,967 people · Surface Water Purchased BEAUMONT CHERRY VALLEY WD BEAUMONT, CA · 66,841 people · Groundwater CAL AMERICAN WATER CO ROSEMEAD, CA · 66,809 people · Surface Water Purchased CITY OF TUSTIN TUSTIN, CA · 66,600 people · Surface Water Purchased CITY OF MADERA MADERA, CA · 66,560 people · Groundwater LAKEWOOD - CITY, WATER DEPT. LAKEWOOD, CA · 66,135 people · Groundwater SUBURBAN WATER SYSTEMS-WHITTIER COVINA, CA · 66,045 people · Groundwater WATSONVILLE, CITY OF WATSONVILLE, CA · 65,231 people · Surface Water BRENTWOOD BRENTWOOD, CA · 64,513 people · Surface Water Purchased LIBERTY UTILITIES (AV RANCHOS) CORP. DOWNEY, CA · 64,469 people · Groundwater CALIFORNIA WATER SERVICE-S SAN FRANCISCO SAN JOSE, CA · 64,146 people · Surface Water Purchased GSWC - FLORENCE/GRAHAM ANAHEIM, CA · 63,500 people · Surface Water Purchased PORTERVILLE, CITY OF PORTERVILLE, CA · 63,487 people · Groundwater CITY OF LA HABRA LA HABRA, CA · 63,118 people · Surface Water Purchased CITY OF PITTSBURG PITTSBURG, CA · 62,500 people · Surface Water Purchased MONTEREY PARK-CITY, WATER DEPT. MONTEREY PARK, CA · 62,183 people · Groundwater HANFORD, CITY OF HANFORD, CA · 62,127 people · Groundwater NORTH MARIN WATER DISTRICT NOVATO, CA · 61,691 people · Surface Water CITY OF WOODLAND WOODLAND, CA · 61,462 people · Surface Water Purchased CALIFORNIA WATER SERVICE - BEAR GULCH SAN JOSE, CA · 61,431 people · Surface Water PETALUMA, CITY OF PETALUMA, CA · 60,781 people · Groundwater CALIFORNIA WATER SERVICE - LIVERMORE SAN JOSE, CA · 60,414 people · Surface Water Purchased CITY OF GILROY GILROY, CA · 59,203 people · Groundwater SUBURBAN WATER SYSTEMS-LA MIRADA COVINA, CA · 56,793 people · Surface Water Purchased CITY OF FOUNTAIN VALLEY FOUNTAIN VALLEY, CA · 56,747 people · Surface Water Purchased GSWC-SAN DIMAS SAN DIMAS, CA · 56,538 people · Surface Water Purchased ALCO WATER SERVICE SALINAS, CA · 56,253 people · Groundwater ROWLAND WATER DISTRICT ROWLAND HEIGHTS, CA · 56,100 people · Surface Water Purchased MONTE VISTA WD MONTCLAIR, CA · 56,017 people · Surface Water Purchased PARAMOUNT - CITY, WATER DEPT. PARAMOUNT, CA · 55,200 people · Surface Water Purchased GSWC - BELL, BELL GARDENS ANAHEIM, CA · 54,877 people · Surface Water Purchased CAL AM - SUBURBAN ROSEMONT SACRAMENTO, CA · 54,793 people · Surface Water Purchased CITY OF LINCOLN LINCOLN, CA · 54,538 people · Surface Water Purchased CERES, CITY OF CERES, CA · 54,513 people · Surface Water Purchased RIALTO, CITY OF RIALTO, CA · 54,453 people · Surface Water Purchased CITY OF WEST SACRAMENTO WEST SACRAMENTO, CA · 53,355 people · Surface Water CITY OF THOUSAND OAKS WATER DEPARTMENT THOUSAND OAKS, CA · 53,157 people · Surface Water Purchased LAKE HEMET MWD HEMET, CA · 52,913 people · Groundwater YUCAIPA VALLEY WATER DISTRICT YUCAIPA, CA · 52,010 people · Surface Water EL TORO WATER DISTRICT LAKE FOREST, CA · 51,800 people · Surface Water Purchased CITY OF SAN CLEMENTE SAN CLEMENTE, CA · 51,545 people · Surface Water Purchased DELANO, CITY OF DELANO, CA · 51,428 people · Groundwater CITY OF ARCADIA ARCADIA, CA · 51,361 people · Groundwater CAL AM - PARKWAY SACRAMENTO, CA · 50,573 people · Surface Water Purchased GOLDEN STATE WC - PLACENTIA/YORBA LINDA ANAHEIM, CA · 50,381 people · Surface Water Purchased GSWC - ARTESIA ANAHEIM, CA · 50,375 people · Groundwater WHITTIER-CITY, WATER DEPT. WHITTIER, CA · 49,954 people · Groundwater GLENDORA-CITY, WATER DEPT. GLENDORA, CA · 49,934 people · Surface Water Purchased POWAY, CITY OF POWAY, CA · 49,888 people · Surface Water UC - DAVIS DAVIS, CA · 49,616 people · Surface Water Purchased CITY OF BREA BREA, CA · 48,479 people · Surface Water Purchased CAL AM - LINCOLN OAKS SACRAMENTO, CA · 48,094 people · Surface Water Purchased CAL/AM WATER COMPANY - SAN MARINO ROSEMEAD, CA · 47,995 people · Surface Water Purchased SAN LUIS OBISPO WATER DEPARTMENT SAN LUIS OBISPO, CA · 47,788 people · Surface Water CERRITOS - CITY, WATER DEPT. CERRITOS, CA · 47,475 people · Surface Water Purchased CITY OF LOS BANOS LOS BANOS, CA · 47,419 people · Groundwater CITY OF MORGAN HILL MORGANN HILL, CA · 47,374 people · Groundwater GOLDEN STATE WATER CO. - CORDOVA RANCHO CORDOVA, CA · 47,161 people · Surface Water CAMARILLO WATER DEPT CAMARILLO, CA · 46,824 people · Surface Water Purchased COLTON, CITY OF COLTON, CA · 46,525 people · Groundwater BELLFLOWER - SOMERSET MWC BELLFLOWER, CA · 46,300 people · Surface Water Purchased CITY OF SAN JOSE - NSJ/ALVISO SAN JOSE, CA · 45,559 people · Surface Water Purchased GOLDEN STATE WATER COMPANY - SIMI VALLEY RANCHO CORDOVA, CA · 45,128 people · Surface Water Purchased OILDALE MWC BAKERSFIELD, CA · 44,899 people · Surface Water Purchased HAWTHORNE-CITY WATER DEPT. SAN JOSE, CA · 44,718 people · Surface Water Purchased ROHNERT PARK, CITY OF ROHNERT PARK, CA · 43,821 people · Groundwater ELK GROVE WATER DISTRICT ELK GROVE, CA · 43,813 people · Surface Water Purchased EL CENTRO, CITY OF EL CENTRO, CA · 43,772 people · Surface Water Purchased COACHELLA WATER AUTHORITY COACHELLA, CA · 43,590 people · Groundwater MISSION SPRINGS WD DESERT HOT SPRINGS, CA · 43,484 people · Groundwater DIABLO WATER DISTRICT OAKLEY, CA · 43,357 people · Surface Water Purchased GSWC - NORWALK ANAHEIM, CA · 43,176 people · Surface Water Purchased CITY OF SAN BRUNO SAN BRUNO, CA · 42,631 people · Surface Water Purchased CAMP PENDLETON (SOUTH) CAMP PENDLETON, CA · 42,219 people · Groundwater INDIAN WELLS VALLEY W.D. RIDGECREST, CA · 41,580 people · Groundwater CARMICHAEL WATER DISTRICT CARMICHAEL, CA · 41,193 people · GWUDI SOUTH COAST WATER DISTRICT LAGUNA BEACH, CA · 41,118 people · Surface Water Purchased CALIFORNIA STATE UNIVERSITY FRESNO FRESNO, CA · 41,000 people · Groundwater SOQUEL CREEK WATER DISTRICT SOQUEL, CA · 40,809 people · Surface Water Purchased PICO RIVERA - CITY, WATER DEPT. PICO RIVERA, CA · 40,600 people · Groundwater LOMPOC-CITY WATER UTILITY DIV LOMPOC, CA · 40,473 people · Surface Water SAN DIEGUITO WD ENCINITAS, CA · 40,405 people · Surface Water Purchased CALEXICO, CITY OF CALEXICO, CA · 40,357 people · Surface Water Purchased BEVERLY HILLS-CITY, WATER DEPT. BEVERLY HILLS, CA · 40,121 people · Surface Water Purchased ADELANTO, CITY OF ADELANTO, CA · 39,930 people · Groundwater GSWC - CLAREMONT SAN DIMAS, CA · 39,730 people · Surface Water Purchased SANTA MARGARITA WATER DISTRICT-ID9 RANCHO SANTA MARGARITA, CA · 39,684 people · Surface Water Purchased SAN GABRIEL COUNTY WD ROSEMEAD, CA · 39,345 people · Groundwater CITY OF LIVERMORE LIVERMORE, CA · 38,892 people · Surface Water Purchased NORTH COAST COUNTY WATER DIST PACIFICA, CA · 38,546 people · Surface Water Purchased MARINA COAST WATER DISTRICT MARINA, CA · 38,377 people · Groundwater GSWC - CULVER CITY ANAHEIM, CA · 38,213 people · Surface Water Purchased TEJON CASTAC WD - I5 & LAVAL RD LEBEC, CA · 38,125 people · Surface Water MONROVIA-CITY, WATER DEPT. MONROVIA, CA · 37,931 people · Groundwater VAUGHN WC INC BAKERSFIELD, CA · 37,189 people · Groundwater RAMONA MUNICIPAL WD RAMONA, CA · 37,047 people · Surface Water Purchased NAS NORTH ISLAND & NAB CORONADO SAN DIEGO, CA · 36,990 people · Surface Water Purchased RUBIDOUX COMMUNITY SD JURUPA VALLEY, CA · 36,827 people · Groundwater TRUCKEE-DONNER PUD, MAIN TRUCKEE, CA · 36,730 people · Groundwater ESTERO MUNICIPAL IMPROVEMENT DISTRICT FOSTER CITY, CA · 36,556 people · Surface Water Purchased FAIR OAKS WATER DISTRICT FAIR OAKS, CA · 36,226 people · Surface Water Purchased STANFORD UNIVERSITY STANFORD, CA · 35,853 people · Surface Water Purchased CRESCENTA VALLEY CWD LA CRESCENTA, CA · 35,841 people · Surface Water Purchased CAL AM - ANTELOPE SACRAMENTO, CA · 35,534 people · Surface Water Purchased VENTURA CWWD NO. 1 - MOORPARK MOORPARK, CA · 35,514 people · Surface Water Purchased LAKESIDE WD LAKESIDE, CA · 35,500 people · Surface Water Purchased CALIFORNIA WATER SERVICE - SAN CARLOS SAN JOSE, CA · 35,344 people · Surface Water Purchased FALLBROOK PUD FALLBROOK, CA · 35,237 people · Surface Water Purchased CITY OF LATHROP LATHROP, CA · 35,080 people · Surface Water Purchased GOLDEN STATE WATER COMPANY - ORCUTT HAWTHORNE, CA · 34,102 people · Surface Water Purchased

California Drinking Water: Frequently Asked Questions

Is California tap water safe to drink?

California has 2,781 community water systems regulated by the EPA serving a combined 43,979,302 people. Water quality varies by system — search above to find your specific utility and see its violation history, lead test results, and safety grade.

How many water systems are in California?

There are 2,781 EPA-regulated community water systems in California serving a combined 43,979,302 people. Each system is required to test for over 90 contaminants and publicly report any violations.

Does California have PFAS in its drinking water?

PFAS (forever chemicals) have been detected in water systems across the country, including California. The EPA finalized enforceable PFAS limits in 2024. Search for your specific water system above to see if PFAS were detected and whether levels exceed the new federal limits.

EPA data last updated: 2026-07-12