California Tap Water Quality

EPA water quality data for 150 community water systems serving 3,388,772+ people in California. Click any system to see violations, lead testing results, and a safety grade.

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.

EAST BAY MUD OAKLAND, CA · 1,442,800 people · Surface Water ALAMEDA COUNTY WATER DISTRICT FREMONT, CA · 344,000 people · Surface Water CONTRA COSTA WATER DISTRICT CONCORD, CA · 198,000 people · Surface Water CITY OF HAYWARD HAYWARD, CA · 162,954 people · Surface Water Purchased EL DORADO ID - MAIN PLACERVILLE, CA · 132,171 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 SOUTH TAHOE PUD - MAIN SOUTH LAKE TAHOE, CA · 100,000 people · Groundwater DUBLIN SAN RAMON SERVICES DISTRICT PLEASANTON, CA · 98,776 people · Surface Water Purchased CITY OF PLEASANTON PLEASANTON, CA · 76,689 people · Surface Water Purchased BRENTWOOD BRENTWOOD, CA · 64,513 people · Surface Water Purchased CITY OF PITTSBURG PITTSBURG, CA · 62,500 people · Surface Water Purchased CALIFORNIA WATER SERVICE - LIVERMORE SAN JOSE, CA · 60,414 people · Surface Water Purchased DIABLO WATER DISTRICT OAKLEY, CA · 43,357 people · Surface Water Purchased CITY OF LIVERMORE LIVERMORE, CA · 38,892 people · Surface Water Purchased CITY OF MARTINEZ MARTINEZ, CA · 30,997 people · Surface Water Purchased GOLDEN STATE WATER COMPANY - BAY POINT RANCHO CORDOVA, CA · 23,731 people · Surface Water Purchased SOUTH FEATHER W&P - MINERS RANCH OROVILLE, CA · 22,664 people · Surface Water CITY OF CRESCENT CITY CRESCENT CITY, CA · 17,262 people · Groundwater TOWN OF DISCOVERY BAY DISCOVERY BAY, CA · 16,790 people · Groundwater THERMALITO WATER & SEWER DIST OROVILLE, CA · 12,136 people · Surface Water CCWD - EBBETTS PASS SAN ANDREAS, CA · 11,545 people · Surface Water CAL-WATER SERVICE CO.-OROVILLE SAN JOSE, CA · 11,106 people · Surface Water DEL ORO WATER CO.-PARADISE PINES CHICO, CA · 10,940 people · Surface Water Purchased CCWD - JENNY LIND SAN ANDREAS, CA · 9,861 people · Surface Water GEORGETOWN DIVIDE PUD GEORGETOWN, CA · 9,434 people · Surface Water PLACERVILLE, CITY OF - MAIN PLACERVILLE, CA · 9,224 people · Surface Water Purchased PARADISE IRRIGATION DISTRICT PARADISE, CA · 9,142 people · Surface Water AWA BUCKHORN PLANT SUTTER CREEK, CA · 8,791 people · Surface Water KIRKWOOD MEADOWS PUBLIC UTILITY DISTRICT KIRKWOOD, CA · 7,851 people · Groundwater CITY OF GRIDLEY GRIDLEY, CA · 7,269 people · Groundwater AWA, IONE SUTTER CREEK, CA · 7,227 people · Surface Water CITY OF COLUSA COLUSA, CA · 6,447 people · Groundwater CALAVERAS PUD SAN ANDREAS, CA · 6,286 people · Surface Water CITY OF WILLIAMS WILLIAMS, CA · 5,538 people · Groundwater CCWD - COPPER COVE SAN ANDREAS, CA · 5,187 people · Surface Water CITY OF JACKSON JACKSON, CA · 5,019 people · Surface Water Purchased AWA, TANNER SUTTER CREEK, CA · 4,940 people · Surface Water BLUE LAKE SPRINGS MUT WTR ARNOLD, CA · 4,841 people · Surface Water Purchased UNION PUBLIC UTILITY DISTRICT MURPHYS, CA · 4,774 people · Surface Water ANGELS, CITY OF ANGELS CAMP, CA · 3,836 people · Surface Water JACKSON VALLEY IRRIGATION DISTRICT IONE, CA · 3,553 people · Surface Water LUKINS BROTHERS WATER COMPANY SOUTH LAKE TAHOE, CA · 3,277 people · Groundwater ARBUCKLE PUBLIC UTILITY DISTRICT ARBUCKLE, CA · 2,778 people · Groundwater LAKESIDE PARK ASSOCIATION SOUTH LAKE TAHOE, CA · 2,648 people · Surface Water BERTSCH OCEAN VIEW CSD CRESCENT CITY, CA · 2,570 people · Groundwater Purchased SMITH RIVER C.S.D. SMITH RIVER, CA · 2,568 people · Groundwater AWA - CAMANCHE VILLAGE SUTTER CREEK, CA · 2,402 people · Groundwater CITY OF BIGGS BIGGS, CA · 2,060 people · Groundwater DURHAM IRRIGATION DISTRICT DURHAM, CA · 1,581 people · Groundwater TAHOE KEYS WATER COMPANY SOUTH LAKE TAHOE, CA · 1,420 people · Groundwater ALAMEDA POINT OAKLAND, CA · 1,400 people · Surface Water Purchased GRIZZLY FLATS COMMUNITY SERVIC GRIZZLY FLATS, CA · 1,374 people · Surface Water MAXWELL PUBLIC UTILITY DISTRICT MAXWELL, CA · 1,175 people · Groundwater PINE GROVE COMM SERV DIST PINE GROVE, CA · 1,141 people · Surface Water Purchased PLYMOUTH, CITY OF PLYMOUTH, CA · 1,060 people · Surface Water Purchased CCWD - WEST POINT SAN ANDREAS, CA · 1,043 people · Surface Water CAMANCHE NORTH SHORE INC. VALLEY SPRINGS, CA · 922 people · Groundwater VALLEY SPRINGS PUD VALLEY SPRINGS, CA · 900 people · Groundwater DEL ORO WATER CO.-LIME SADDLE MARINA CHICO, CA · 895 people · Surface Water FIRST MACE MEADOW # 1 PINE GROVE, CA · 838 people · Surface Water Purchased CAMANCHE SOUTH SHORE-EBMUD VALLEY SPRINGS, CA · 828 people · Surface Water TAHOE CITY PUD - RUBICON TAHOE CITY, CA · 703 people · Groundwater SNOWSHOE SPRINGS ASSN. ARNOLD, CA · 686 people · Surface Water Purchased GASQUET C.S.D. GASQUET, CA · 657 people · Surface Water BIG ROCK C.S.D. CRESCENT CITY, CA · 650 people · Groundwater PLEASANTIMES MUTUAL WATER CO BETHEL ISLAND, CA · 644 people · Groundwater LAKE ALPINE WATER COMPANY BEAR VALLEY, CA · 625 people · Surface Water RIVER PINES PUD RIVER PINES, CA · 574 people · Groundwater CLAYTON PALMS WATER CLAYTON, CA · 549 people · Surface Water Purchased LANARE COMMUNITY SERVICES DIST COALINGA, CA · 540 people · Groundwater EL DORADO ID - OUTINGDALE PLACERVILLE, CA · 535 people · Surface Water CASTLEWOOD DOMESTIC WATER SYSTEM PLEASANTON, CA · 524 people · Groundwater Purchased DEL ORO WATER CO.-STIRLING BLUFFS CHICO, CA · 521 people · Surface Water COLUSA CO. WWD #1 - GRIMES GRIMES, CA · 512 people · Groundwater WILLOW MOBILE HOME PARK MARTINEZ, CA · 481 people · Groundwater GRIDLEY FARM LABOR HOUSING CHICO, CA · 460 people · Groundwater TRAILER HAVEN MOBILE HOME PARK SACRAMENTO, CA · 459 people · Surface Water Purchased FCSA 05 - WILDWOOD ISLAND FRESNO, CA · 417 people · Groundwater EL DORADO ID - STRAWBERRY PLACERVILLE, CA · 400 people · Surface Water BUTTE CREEK ESTATES MUTUAL WATER CO CHICO, CA · 399 people · Groundwater COLUSA CO. WWD #2 - PRINCETON PRINCETON, CA · 382 people · Groundwater WILLOW PARK MARINA OAKLEY, CA · 380 people · Groundwater LAS DELTAS MUTUAL WATER COMPANY CLOVIS, CA · 375 people · Groundwater Purchased KLAMATH C.S.D. KLAMATH, CA · 360 people · Groundwater ORWOOD RESORT BRENTWOOD, CA · 350 people · Groundwater SHAVER LAKE HEIGHTS WATER ASSN PRATHER, CA · 345 people · Groundwater DEL ORO WATER CO.-MAGALIA CHICO, CA · 340 people · Groundwater DELTA MUTUAL WATER COMPANY OAKLEY, CA · 333 people · Groundwater PLEASANT GROVE MHP OROVILLE, CA · 327 people · Groundwater EASTON ESTATES WATER COMPANY FRESNO, CA · 302 people · Groundwater HOPE FOUNDATION/MORIAH HEIGHTS PLYMOUTH, CA · 299 people · Groundwater LAKE MADRONE WATER DISTRICT BERRY CREEK, CA · 297 people · Groundwater FCWWD 42/ALLUVIAL & FANCHER FRESNO, CA · 291 people · Groundwater GRAN MUTUAL WATER CO CHICO, CA · 290 people · Groundwater ANGELS CAMP RV/CAMPING RESORT ANGELS CAMP, CA · 288 people · Groundwater TOWN OF SUNOL - SFPUC BURLINGAME, CA · 281 people · Surface Water Purchased GOLDEN FEATHER MHP SACRAMENTO, CA · 275 people · Groundwater BELMONT WATER CORPORATION FRESNO, CA · 264 people · Groundwater CCWD - WALLACE SAN ANDREAS, CA · 255 people · Groundwater ALMOND GROVE MOBILE PARK CHICO, CA · 253 people · Groundwater COLUSA CO. SERVICE AREA #2-STONYFORD CITY OF COLUSA, CA · 250 people · Groundwater NORTHCREST MOBILE HOME PARK SAN DIEGO, CA · 250 people · Groundwater COLUSA CO. SERVICE AREA #1-CENTURY RANCH CITY OF COLUSA, CA · 246 people · Surface Water FCSA 30 - EL PORVENIR FRESNO, CA · 241 people · Surface Water MEADOW LAKES CLUB FRESNO, CA · 240 people · Groundwater FIRST MACE MEADOWS UNIT NO. 2 PINE GROVE, CA · 230 people · Surface Water Purchased RIVERVIEW WATER ASSOCIATION BETHEL ISLAND, CA · 230 people · Groundwater DRYTOWN COUNTY WATER DISTRICT IONE, CA · 221 people · Surface Water Purchased DINGERVILLE USA PARK YORBA LINDA, CA · 220 people · Groundwater CAMINO MOBILEHOME OAKLEY, CA · 210 people · Groundwater BETHEL ISLAND ESTATES SACRAMENTO, CA · 200 people · Groundwater REDWOOD PARK C.S.D. KLAMATH, CA · 200 people · Groundwater FCWWD 40 - SHAVER SPRINGS FRESNO, CA · 196 people · Groundwater AWA LA MEL HEIGHTS #3 SUTTER CREEK, CA · 188 people · Groundwater DEL ORO WC - ARBUCKLE DISTRICT CHICO, CA · 185 people · Groundwater BETHEL ISLAND MHC STOCKTON, CA · 185 people · Groundwater HRC C.S.D. CRESCENT CITY, CA · 185 people · Groundwater FCWWD 38/SKY HARBOUR FRESNO, CA · 185 people · Groundwater FOOTHILLS MANUFACTURED HOME COMMUNUTY OROVILLE, CA · 180 people · Groundwater MARKLEEVILLE WATER CO. MARKLEEVILLE, CA · 175 people · Surface Water OAKLEY MUTUAL WATER COMPANY OAKLEY, CA · 170 people · Groundwater KEEFER CREEK ESTATES CHICO, CA · 160 people · Groundwater BIG OAK MOBILE HOME PARK WATER OAKLEY, CA · 156 people · Groundwater YOUTH WITH A MISSION-SPRINGS OF LIVING W RICHARDSON SPRINGS, CA · 150 people · Groundwater RITE OF PASSAGE/SIERRA RIDGE SAN ANDREAS, CA · 150 people · Surface Water KYBURZ MUTUAL WATER COMPANY KYBURZ, CA · 150 people · Surface Water PINE GROVE MOBILE HOME PARK SAN DIEGO, CA · 142 people · Groundwater FARRAR PARK PROPERTY OWNERS BETHEL ISLAND RD, CA · 140 people · Groundwater GOLD BEACH PARK STOCKTON, CA · 134 people · Groundwater FCSA 10 - CUMORAH KNOLLS FRESNO, CA · 132 people · Groundwater FCWWD 37/MILE HIGH FRESNO, CA · 129 people · Groundwater RIVERVIEW MOBILE HOME PARK SACRAMENTO, CA · 126 people · Groundwater BETHEL ISLAND MUTUAL WATER CO BETHEL ISLAND, CA · 123 people · Groundwater SIERRA MOON MUTUAL WATER COMPANY CHICO, CA · 120 people · Groundwater LAS PALMAS MOBILE HOME PARK EUREKA, CA · 120 people · Groundwater NEW AUBERRY WATER ASSOCIATION AUBERRY, CA · 120 people · Groundwater FOREST RANCH MUTUAL WATER SYSTEM FOREST RANCH, CA · 119 people · Groundwater FCSA 14 - BELMONT MANOR FRESNO, CA · 115 people · Groundwater WEST PARK PROPERTIES CRESCENT CITY, CA · 112 people · Groundwater CRYSTAL CAVES MHP PLACERVILLE, CA · 112 people · Groundwater RUSSOS MOBILE PARK BETHEL ISLAND, CA · 110 people · Groundwater DEL ORO WATER COMPANY - BUZZTAIL DIST. CHICO, CA · 106 people · Groundwater VOLCANO COMMUNITY SERVICE DIST VOLCANO, CA · 103 people · GWUDI FIDDLETOWN COMMUNITY SERVICE FIDDLETOWN, CA · 100 people · Groundwater SANDMOUND MUTUAL BETHEL ISLAND, CA · 100 people · Groundwater BEAR STATE WATER WORKS GEORGETOWN, CA · 100 people · Groundwater LILI VALLEY WATER CO. WEST POINT, CA · 99 people · Groundwater DUNROVIN MOBILE HOME VILLAGE CONCORD, CA · 99 people · Groundwater ANGLERS SUBDIVISION 4 BETHEL ISLAND, CA · 99 people · Groundwater