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PFAS in California drinking water

690 community water systems tested

23.6%
of tested systems detected PFOA or PFOS
(163/690)

PFAS — “forever chemicals” — are synthetic compounds that accumulate in the body and are linked to cancer, liver damage and immune effects. In 2024 the EPA set enforceable limits of 4 parts per trillion each for PFOA and PFOS. These are the only nationwide PFAS measurements, from the EPA’s UCMR-5 program.

Water systems

PFAS value per system, 2023–2025. EPA limit — 4 ppt (0.004 µg/L) for PFOA and PFOS, set in 2024. Systems that detected PFOA or PFOS are highlighted and listed first. “Not detected” means the contaminant was measured but not found.
SystemCityPopulationPFAS (ug/L)
RUNNING SPRINGS WATER DISTRICT 5,268 0.2365 ug/L
LIBERTY UTILITIES - BELLFLOWER-NORWALK 72,624 0.0590 ug/L
MONTEBELLO LAND & WATER CO. 26,554 0.0530 ug/L
CITY OF ATWATER ATWATER 29,479 0.0450 ug/L
DOWNEY - CITY, WATER DEPT. DOWNEY 110,556 0.0440 ug/L
CITY OF SACRAMENTO MAIN SACRAMENTO 527,979 0.0414 ug/L
CITY OF CLOVIS CLOVIS 130,130 0.0410 ug/L
TRACT 349 MUTUAL WATER CO. 8,700 0.0365 ug/L
ATASCADERO STATE HOSPITAL 4,100 0.0330 ug/L
BELLFLOWER MUNICIPAL WATER SYSTEM 5,999 0.0326 ug/L
NORCO, CITY OF NORCO 25,068 0.0314 ug/L
CITY OF FRESNO FRESNO 545,716 0.0300 ug/L
ONTARIO MUNICIPAL UTILITIES COMPANY ONTARIO 185,010 0.0300 ug/L
PICO RIVERA - CITY, WATER DEPT. PICO RIVERA 40,600 0.0300 ug/L
CITY OF ANAHEIM ANAHEIM 348,593 0.0290 ug/L
PICO WD 22,051 0.0280 ug/L
MAYWOOD MUTUAL WATER CO. #3 6,059 0.0264 ug/L
MODESTO, CITY OF MODESTO 218,771 0.0260 ug/L
CITY OF PLEASANTON PLEASANTON 76,689 0.0260 ug/L
SOUTH GATE-CITY, WATER DEPT. SOUTH GATE 76,443 0.0260 ug/L
NORWALK - CITY, WATER DEPT. NORWALK 20,283 0.0260 ug/L
SCWA - LAGUNA/VINEYARD 184,896 0.0240 ug/L
CERES, CITY OF CERES 54,513 0.0240 ug/L
TRACT 180 MUTUAL WATER CO. 14,000 0.0240 ug/L
LYNWOOD-CITY, WATER DEPT. LYNWOOD 66,967 0.0230 ug/L
PORTERVILLE, CITY OF PORTERVILLE 63,487 0.0230 ug/L
ORCHARD DALE WATER DISTRICT 25,000 0.0230 ug/L
HUNTINGTON PARK-CITY, WATER DEPT. HUNTINGTON PARK 15,437 0.0230 ug/L
CITY OF BELL GARDENS BELL GARDENS 11,437 0.0230 ug/L
HELENDALE COMMUNITY SERVICE DISTRICT 6,347 0.0230 ug/L
LA HABRA HEIGHTS CWD 5,325 0.0230 ug/L
CAL-WATER SERVICE CO.-CHICO 114,925 0.0225 ug/L
ATASCADERO MUTUAL WATER CO 30,618 0.0223 ug/L
GSWC-SOUTH ARCADIA 27,072 0.0220 ug/L
SOUTH MONTEBELLO IRRIGATION DIST. 15,021 0.0201 ug/L
CITY OF GARDEN GROVE GARDEN GROVE 174,226 0.0190 ug/L
RIVERSIDE HIGHLAND WATER COMPANY 20,188 0.0190 ug/L
RUBIO CANON LAND & WATER ASSOCIATION 9,215 0.0190 ug/L
WEAVERVILLE C.S.D. 3,975 0.0190 ug/L
GOLDEN HILLS CSD 9,857 0.0186 ug/L
POMONA - CITY, WATER DEPT. POMONA 151,713 0.0180 ug/L
COLTON, CITY OF COLTON 46,525 0.0180 ug/L
CITY OF ORANGE ORANGE 120,770 0.0170 ug/L
COMPTON-CITY, WATER DEPT. COMPTON 74,877 0.0170 ug/L
BELLFLOWER - SOMERSET MWC 46,300 0.0170 ug/L
CITY OF LATHROP LATHROP 35,080 0.0170 ug/L
CAMROSA WATER DISTRICT 32,700 0.0170 ug/L
LIBERTY UTILITIES - LYNWOOD 24,701 0.0170 ug/L
SANTA CLARITA VALLEY WATER AGENCY 294,090 0.0169 ug/L
LAKEWOOD - CITY, WATER DEPT. LAKEWOOD 66,135 0.0167 ug/L
CITY OF REDDING REDDING 89,628 0.0162 ug/L
RANCHO CALIFORNIA WATER DISTRICT 146,147 0.0160 ug/L
GOLDEN STATE WC - WEST ORANGE COUNTY 114,379 0.0160 ug/L
SUBURBAN WATER SYSTEMS-LA MIRADA 56,793 0.0160 ug/L
GLENDALE-CITY, WATER DEPT. GLENDALE 188,784 0.0158 ug/L
GSWC - BELL, BELL GARDENS 55,050 0.0150 ug/L
CAL AM - PARKWAY 50,573 0.0147 ug/L
LOS OSOS COMMUNITY SERVICES DISTRICT 7,086 0.0147 ug/L
PLANADA CSD 4,164 0.0147 ug/L
CITY OF SANTA ANA SANTA ANA 310,539 0.0142 ug/L
CWS - BAKERSFIELD 267,881 0.0140 ug/L
SANTA FE SPRINGS - CITY, WATER DEPT. SANTA FE SPRINGS 19,219 0.0140 ug/L
CALIFORNIA STATE FAIR 9,280 0.0140 ug/L
LAKE ARROWHEAD CSD 7,038 0.0140 ug/L
SAN JOAQUIN COUNTY-MOKELUMNE ACRES 3,802 0.0135 ug/L
CAL AM - SUBURBAN ROSEMONT 54,793 0.0134 ug/L
CITY OF FULLERTON FULLERTON 139,461 0.0133 ug/L
SUBURBAN WATER SYSTEMS-WHITTIER 66,045 0.0130 ug/L
GSWC - ARTESIA 50,415 0.0130 ug/L
GSWC - CLAREMONT 39,730 0.0129 ug/L
CALISTOGA, CITY OF CALISTOGA 5,610 0.0122 ug/L
EAST VALLEY WATER DISTRICT 108,629 0.0120 ug/L
CALIFORNIA WATER SERVICE - LIVERMORE 60,414 0.0120 ug/L
CALIFORNIA STATE UNIVERSITY FRESNO 41,000 0.0120 ug/L
PINEDALE COUNTY WATER DISTRICT 16,736 0.0120 ug/L
RIPON, CITY OF RIPON 15,741 0.0120 ug/L
FLORIN COUNTY WATER DISTRICT 7,831 0.0118 ug/L
SWEETWATER AUTHORITY 191,282 0.0114 ug/L
MAYWOOD MUTUAL WATER CO. #1 5,500 0.0113 ug/L
HESPERIA WD 100,744 0.0111 ug/L
LINDSAY, CITY OF LINDSAY 12,659 0.0110 ug/L
PLEASANT VALLEY MUTUAL WATER CO 5,000 0.0110 ug/L
CITY OF WHEATLAND WHEATLAND 4,124 0.0110 ug/L
CITY OF GRIDLEY GRIDLEY 7,269 0.0105 ug/L
CITY OF VACAVILLE VACAVILLE 99,650 0.0100 ug/L
CITY OF ARCADIA ARCADIA 51,361 0.0100 ug/L
BIG BEAR CITY CSD BIG BEAR CITY 12,738 0.0099 ug/L
GUADALUPE VALLEY MID 1,472 0.0096 ug/L
COMMERCE-CITY, WATER DEPT. MONTEBELLO 4,205 0.0093 ug/L
CITY OF MERCED MERCED 93,692 0.0089 ug/L
Rincon Northern 7,003 0.0089 ug/L
CALIFORNIA WATER SERVICE CO. - ELA 152,474 0.0086 ug/L
CAL AM - MEADOWBROOK 5,656 0.0083 ug/L
CAL AM WATER COMPANY - MONTEREY 92,450 0.0081 ug/L
CITY OF GILROY GILROY 59,203 0.0080 ug/L
YOSEMITE SPRING PARK UTIL CO 5,300 0.0079 ug/L
AZUSA LIGHT AND WATER 110,044 0.0077 ug/L
BAKERSFIELD, CITY OF BAKERSFIELD 160,144 0.0076 ug/L
UKIAH, CITY OF UKIAH 16,607 0.0074 ug/L
CITY OF RED BLUFF RED BLUFF 14,710 0.0074 ug/L