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Results for Contra Costa County, CA

179 water providers on file for this county, sorted by population served.

Quick answer: Contra Costa County has 179 water providers profiled, sorted by population served.

Lead Summary
Nitrate
Nitrate-Nitrite
Aggressive Index
Langelier Index (pH(s))
Magnesium
Potassium
Sodium
Hardness, Total (ASCACO3)
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
TDS
Chloride
Sulfate
Fluoride
Turbidity
pH, Field
Boron, Total
Iron
Manganese
Chromium
Selenium
Zinc
Conductivity (at 25°C)
pH
Odor
Chromium, Hex
Perchlorate
Barium
Cyanide
Color
Arsenic
Copper, Free
Copper Summary
Lead
Totalhaloaceticacids (HAA5)
Dibromoaceticacid
Gross Alpha Particle Activity
Toluene
Vanadium, Total
Perfluorobutanesulfonicacid (PFBS)
Perfluoroheptanoicacid (PFHPA)
Perfluorohexanesulfonicacid (PFHxS)
Perfluoroctanesulfonicacid (PFOS)
Perfluoroctanoicacid (PFOA)
Perfluorohexanoicacid (PFHXA)
Perfluorobutanoicacid (PFBA)
Perfluoropentanoicacid (PFPEA)
Gross Beta Particle Activity
TTHM
Bromoform
Dibromochloromethane
Chloroform
Bromodichloromethane
Dichloroaceticacid
Trichloroaceticacid
Orthophosphate
Nickel
Aluminum
Nitrogen-Ammoniaas (N)
Monochloroaceticacid
Lithium
Bromide
Radium-228
Combined Radium (-226 & -228)
Monobromoaceticacid
Perfluoropentanesulfonicacid (PFPES)
Perfluoroheptanesulfonicacid (PFHPS)

Violations on file

Coliform (TCR)

Older/archived health-based violation

Found at 7 of 179 providers

Nitrate

Older/archived health-based violation

Found at 6 of 179 providers

Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.

Selenium

Older/archived health-based violation

Found at 1 of 179 providers

Lead And Copper Rule Revisions

Currently open health violation

Found at 8 of 179 providers

Arsenic

Older/archived health-based violation

Found at 4 of 179 providers

Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.

Contaminants found

Metals

Naturally occurring or corrosion-related elements, e.g. lead, arsenic, copper

Lead Summary

Detected: 0.024 mg/L (ppm)

Found at 51 providers

Iron

Detected: 1400 UG/L (ppb)

Found at 9 providers

Mostly an aesthetic issue (metallic taste, staining) rather than a health concern at typical levels.

Manganese

Detected: 420 UG/L (ppb)

Found at 14 providers

Mainly a taste/staining concern at typical levels; long-term neurological research at high chronic exposure is ongoing.

Chromium

Detected: 25 UG/L (ppb)

Found at 5 providers

Occurs in two forms — trivalent (an essential nutrient in trace amounts) and hexavalent (linked to increased cancer risk).

Selenium

Detected: 12 UG/L (ppb)

Found at 5 providers

Zinc

Detected: 20 UG/L (ppb)

Found at 4 providers

Chromium, Hex

Detected: 12.9 UG/L (ppb)

Found at 12 providers

Barium

Detected: 310 UG/L (ppb)

Found at 7 providers

Arsenic

Detected: 18 UG/L (ppb)

Found at 13 providers

Occurs naturally in some groundwater. Long-term exposure above the legal limit (10 ppb) has been linked to increased cancer risk and cardiovascular disease.

Copper, Free

Detected: 200 UG/L (ppb)

Found at 13 providers

Copper Summary

Detected: 104 mg/L (ppm)

Found at 3 providers

Lead

Detected: 9 UG/L (ppb)

Found at 3 providers

A metal that can leach from old pipes, solder, and fixtures. Current medical guidance holds there is no truly safe level of lead exposure, especially for children and pregnant women.

Vanadium, Total

Detected: 8.7 UG/L (ppb)

6/26/2025

Nickel

Detected: 2 UG/L (ppb)

Found at 2 providers

Aluminum

Detected: 400 UG/L (ppb)

Found at 3 providers

Disinfection Byproducts

Formed when chlorine used to disinfect water reacts with organic matter

Totalhaloaceticacids (HAA5)

Detected: 15 UG/L (ppb)

Found at 12 providers

TTHM

Detected: 57 UG/L (ppb)

Found at 12 providers

A group of disinfection byproducts formed when chlorine reacts with organic matter. Long-term exposure above the legal limit has been linked to increased cancer risk in some studies.

Bromoform

Detected: 29 UG/L (ppb)

Found at 12 providers

Dibromochloromethane

Detected: 21 UG/L (ppb)

Found at 12 providers

Chloroform

Detected: 14 UG/L (ppb)

Found at 11 providers

One of the individual trihalomethane disinfection byproducts, formed when chlorine reacts with organic matter.

Bromodichloromethane

Detected: 14 UG/L (ppb)

Found at 11 providers

Inorganics

Common dissolved minerals and salts, e.g. nitrate, fluoride, chloride

Nitrate

Detected: 8.6 MG/L (ppm)

Found at 30 providers

Commonly from agricultural fertilizer runoff or septic systems. Above the legal limit, it's an immediate concern especially for infants.

Nitrate-Nitrite

Detected: 5 MG/L (ppm)

Found at 9 providers

Chloride

Detected: 390 MG/L (ppm)

Found at 16 providers

Sulfate

Detected: 220 MG/L (ppm)

Found at 17 providers

Fluoride

Detected: 0.73 MG/L (ppm)

Found at 12 providers

Often added deliberately for dental health; can also occur naturally.

Boron, Total

Detected: 4300 UG/L (ppb)

Found at 14 providers

Minerals

Everyday minerals that mainly affect taste and water hardness

Magnesium

Detected: 55 MG/L (ppm)

Found at 16 providers

Potassium

Detected: 4.3 MG/L (ppm)

Found at 16 providers

Sodium

Detected: 234 MG/L (ppm)

Found at 16 providers

Calcium

Detected: 107 MG/L (ppm)

Found at 16 providers

Properties

General water characteristics like pH, hardness, and cloudiness (turbidity)

Langelier Index (pH(s))

Detected: 0.7 LANG

Found at 5 providers

Hardness, Total (ASCACO3)

Detected: 493 MG/L (ppm)

Found at 16 providers

pH, Field

Detected: 8 PH

Found at 5 providers

Detected: 8.65 PH

Found at 11 providers

A measure of how acidic or basic the water is (7 is neutral). Affects taste and plumbing, not a direct health measure.

Gross Alpha Particle Activity

Detected: 19.7 PCI/L

Found at 6 providers

Orthophosphate

Detected: 0.079 MG/L (ppm)

6/12/2025

PFAS & Emerging Contaminants

Human-made "forever chemicals" and other substances not yet fully regulated

Lithium

Detected: 70.7 µg/L (ppb)

Found at 4 providers

Occurs naturally in some groundwater. Not currently federally regulated in drinking water.

VOCs (Volatile Organic Compounds)

Industrial solvents and fuel-related chemicals that evaporate easily

Bromide

Detected: 0.15 MG/L (ppm)

1/14/2025

Petroleum Compounds

Substances associated with fuel or petroleum contamination

Toluene

Detected: 3.6 UG/L (ppb)

2/24/2025

Calculated Parameters

Values worked out mathematically from other test results, not measured directly

Alkalinity, Bicarbonate

Detected: 390 MG/L (ppm)

Found at 17 providers

Other

Additional substances tested that don't fit neatly into the categories above

Aggressive Index

Detected: 12.69 AGGR

Found at 9 providers

Alkalinity, Total

Detected: 320 MG/L (ppm)

Found at 17 providers

TDS

Detected: 1390 MG/L (ppm)

Found at 18 providers

Turbidity

Detected: 9.4 NTU

Found at 13 providers

A measure of water cloudiness from suspended particles.

Conductivity (at 25°C)

Detected: 2180 UMHO/CM

Found at 17 providers

Odor

Detected: 4 TON

Found at 10 providers

Perchlorate

Detected: 13 UG/L (ppb)

Found at 2 providers

Can occur naturally or from industrial/military sources; may interfere with thyroid function at elevated levels.

Cyanide

Detected: 1.7 UG/L (ppb)

Found at 4 providers

Color

Detected: 15 UNITS

Found at 5 providers

Dibromoaceticacid

Detected: 11 UG/L (ppb)

Found at 12 providers

Perfluorobutanesulfonicacid (PFBS)

Detected: 14 NG/L (ppt)

Found at 2 providers

Perfluoroheptanoicacid (PFHPA)

Detected: 3.1 NG/L (ppt)

Found at 2 providers

Perfluorohexanesulfonicacid (PFHxS)

Detected: 97 NG/L (ppt)

Found at 2 providers

Perfluoroctanesulfonicacid (PFOS)

Detected: 110 NG/L (ppt)

Found at 2 providers

One of two PFAS with an enforceable federal limit (4 ppt) since 2024.

Perfluoroctanoicacid (PFOA)

Detected: 4.6 NG/L (ppt)

Found at 2 providers

One of two PFAS with an enforceable federal limit (4 ppt) since 2024.

Perfluorohexanoicacid (PFHXA)

Detected: 13 NG/L (ppt)

Found at 2 providers

Perfluorobutanoicacid (PFBA)

Detected: 8.5 NG/L (ppt)

Found at 2 providers

Perfluoropentanoicacid (PFPEA)

Detected: 16 NG/L (ppt)

Found at 2 providers

Gross Beta Particle Activity

Detected: 16.8 PCI/L

Found at 3 providers

Dichloroaceticacid

Detected: 6.3 UG/L (ppb)

Found at 11 providers

Trichloroaceticacid

Detected: 4.5 UG/L (ppb)

Found at 11 providers

Nitrogen-Ammoniaas (N)

Detected: 0.55 MG/L (ppm)

Found at 4 providers

Monochloroaceticacid

Detected: 6 UG/L (ppb)

Found at 3 providers

Radium-228

Detected: 0.68 PCI/L

6/18/2025

Combined Radium (-226 & -228)

Detected: 0.715 PCI/L

6/18/2025

A naturally occurring radioactive element found in some groundwater.

Monobromoaceticacid

Detected: 1.2 UG/L (ppb)

Found at 2 providers

Perfluoropentanesulfonicacid (PFPES)

Detected: 13 NG/L (ppt)

1/29/2025

Perfluoroheptanesulfonicacid (PFHPS)

Detected: 4 NG/L (ppt)

1/29/2025

Filtration considerations: General system types, not a specific product recommendation.

Contaminant	Whole-House Carbon	Under-Sink RO	Under-Sink Carbon
Total Trihalomethanes (TTHM)	Yes	Yes	Yes
Haloacetic Acids (HAA5)	Yes	Yes	Yes
Chloroform	Yes	Yes	Yes
Chlorine / Taste	Yes	Yes	Yes
Sediment / Turbidity	Yes	Yes	Yes
Trichloroethylene	Yes	Yes	Yes
Tetrachloroethylene	Yes	Yes	Yes
cis-1,2-Dichloroethylene	Yes	Yes	Yes
1,1-Dichloroethylene	Yes	Yes	Yes
Bromoform	Yes	Yes	Yes
Bromodichloromethane	Yes	Yes	Yes
Dibromochloromethane	Yes	Yes	Yes
1,1,2-Trichloroethane	Yes	Yes	Yes
Vinyl Chloride	Yes	Yes	Yes
Carbon Tetrachloride	Yes	Yes	Yes
Benzene	Yes	Yes	Yes
Toluene	Yes	Yes	Yes
Xylene	Yes	Yes	Yes
Totalhaloaceticacids (HAA5)	Yes	Yes	Yes
Bromide	Yes	Yes	Yes
Lead	Partial	Yes	Partial
Arsenic	Partial	Yes	Partial
Chromium-6 (Hexavalent)	Partial	Yes	Partial
Copper	Partial	Yes	Partial
Combined Uranium	Partial	Yes	Partial
PFOA	Partial	Yes*	Partial
PFOS	Partial	Yes*	Partial
Nitrate	Partial	Yes	Partial
Combined Radium	Partial	Yes	Partial
Nitrate-Nitrite	Partial	Yes	Partial
Aggressive Index	Partial	Yes	Partial
Alkalinity, Total	Partial	Yes	Partial
TDS	Partial	Yes	Partial
Chloride	Partial	Yes	Partial
Sulfate	Partial	Yes	Partial
Fluoride	Partial	Yes	Partial
Boron, Total	Partial	Yes	Partial
Iron	Partial	Yes	Partial
Manganese	Partial	Yes	Partial
Chromium	Partial	Yes	Partial
Selenium	Partial	Yes	Partial
Zinc	Partial	Yes	Partial
Conductivity (at 25°C)	Partial	Yes	Partial
Odor	Partial	Yes	Partial
Chromium, Hex	Partial	Yes	Partial
Perchlorate	Partial	Yes	Partial
Barium	Partial	Yes	Partial
Cyanide	Partial	Yes	Partial
Color	Partial	Yes	Partial
Copper, Free	Partial	Yes	Partial
Dibromoaceticacid	Partial	Yes	Partial
Vanadium, Total	Partial	Yes	Partial
Perfluorobutanesulfonicacid (PFBS)	Partial	Yes	Partial
Perfluoroheptanoicacid (PFHPA)	Partial	Yes	Partial
Perfluorohexanesulfonicacid (PFHxS)	Partial	Yes	Partial
Perfluoroctanesulfonicacid (PFOS)	Partial	Yes	Partial
Perfluoroctanoicacid (PFOA)	Partial	Yes	Partial
Perfluorohexanoicacid (PFHXA)	Partial	Yes	Partial
Perfluorobutanoicacid (PFBA)	Partial	Yes	Partial
Perfluoropentanoicacid (PFPEA)	Partial	Yes	Partial
Gross Beta Particle Activity	Partial	Yes	Partial
Dichloroaceticacid	Partial	Yes	Partial
Trichloroaceticacid	Partial	Yes	Partial
Nickel	Partial	Yes	Partial
Aluminum	Partial	Yes	Partial
Nitrogen-Ammoniaas (N)	Partial	Yes	Partial
Monochloroaceticacid	Partial	Yes	Partial
Lithium	Partial	Yes*	Partial
Combined Radium (-226 & -228)	Partial	Yes	Partial
Monobromoaceticacid	Partial	Yes	Partial
Perfluoropentanesulfonicacid (PFPES)	Partial	Yes	Partial
Perfluoroheptanesulfonicacid (PFHPS)	Partial	Yes	Partial
Coliform Bacteria (indicator)	No	Yes	No
Langelier Index (pH(s))	No	No	No
Magnesium	No	Partial	No
Potassium	No	Partial	No
Sodium	No	Partial	No
Hardness, Total (ASCACO3)	No	No	No
Calcium	No	Partial	No
Alkalinity, Bicarbonate	No	No	No
pH, Field	No	No	No
pH	No	No	No
Gross Alpha Particle Activity	No	No	No
Orthophosphate	No	No	No

Browse by city

Individual water providers

CONTRA COSTA WATER DISTRICT No violations on file — pop. 198,000
CITY OF ANTIOCH No violations on file — pop. 115,074 — serves ANTIOCH
BRENTWOOD Older violation on record — pop. 64,513 — serves BRENTWOOD
CITY OF PITTSBURG No violations on file — pop. 62,500 — serves PITTSBURG
DIABLO WATER DISTRICT No violations on file — pop. 43,357
CITY OF MARTINEZ No violations on file — pop. 30,997 — serves MARTINEZ
GOLDEN STATE WATER COMPANY - BAY POINT No violations on file — pop. 23,731
TOWN OF DISCOVERY BAY No violations on file — pop. 16,790
EAST BAY REGIONAL PARK DIST No violations on file — pop. 800
MAGALIA COUNTY WATER DISTRICT No violations on file — pop. 750
PLEASANTIMES MUTUAL WATER CO No violations on file — pop. 644
GAYLORD CONTAINER COMPANY No violations on file — pop. 600

MORRELL PROPERTY MGT Older violation on record — pop. 600
EXCELSIOR MIDDLE SCHOOL No violations on file — pop. 600
MARATHON MARTINEZ WATER SYSTEM No violations on file — pop. 600
CLAYTON PALMS WATER No violations on file — pop. 549
WILLOW MOBILE HOME PARK No violations on file — pop. 481
LUNDBORG LANDING *CL 2/09 Older violation on record — pop. 420
WILLOW PARK MARINA Older violation on record — pop. 380
MOUNT DIABLO STATE PARK No violations on file — pop. 364
KNIGHTSEN ELEMENTARY SCHOOL No violations on file — pop. 350
ORWOOD RESORT Open violation — pop. 350
BEN KUTCH No violations on file — pop. 345
DELTA MUTUAL WATER COMPANY Older violation on record — pop. 333
JEHOVAHS WITNESSE CHURCH *CL 2/13 No violations on file — pop. 300
LIGHTHOUSE BAPTIST CHURCH No violations on file — pop. 250
NEIGHBORHOOD CHURCH No violations on file — pop. 250
CANYON SCHOOL Open violation — pop. 238
RIVERVIEW WATER ASSOCIATION No violations on file — pop. 230
CAMINO MOBILEHOME No violations on file — pop. 210
BYRON CORNERS INC No violations on file — pop. 205
CHURCH OF JESUS CHRIST Older violation on record — pop. 200
BLAZING SADDLE BAR & GRILL No violations on file — pop. 200
BETHEL ISLAND ESTATES No violations on file — pop. 200
COUNTRY JUNCTION DELI No violations on file — pop. 200
BRUNS MEMORIAL AMPHITHEATER No violations on file — pop. 200
CSP BENICIA STATE PARK No violations on file — pop. 191 — serves NC PARK RES
BETHEL ISLAND MHC No violations on file — pop. 185
LOS VAQUEROS MARINA BLDG No violations on file — pop. 180
DWR DELTA FIELD DIVISION - BANKS PP No violations on file — pop. 180
OAKLEY MUTUAL WATER COMPANY Open violation — pop. 170
JOE BROWN, MANAGER No violations on file — pop. 160
BIG OAK MOBILE HOME PARK WATER No violations on file — pop. 156
LIA HONA CLUB L.D.S. No violations on file — pop. 150
SUGAR BARGE MARINA No violations on file — pop. 150
DELTA SPORTSMAN No violations on file — pop. 150
WILLOW PASS MOBILE HOME *CL 1/07-INACTIV No violations on file — pop. 140
FARRAR PARK PROPERTY OWNERS No violations on file — pop. 140
RIVERVIEW MOBILE HOME PARK No violations on file — pop. 126
LABORERS TRAINING AND RETRAINI No violations on file — pop. 125
BETHEL ISLAND MUTUAL WATER CO No violations on file — pop. 123
CONCORD MT DIABLO TRAILRIDE ASSOC. No violations on file — pop. 120
GAS N SAVE No violations on file — pop. 120
EBRPD ALHAMBRA No violations on file — pop. 115
RUSSOS MOBILE PARK Open violation — pop. 110
NORTHGATE MUTUAL WATER No violations on file — pop. 105
EBRPD BAY POINT REGIONAL SHORELINE No violations on file — pop. 105 — serves PITTSBURG
HOLY CROSS CEMETERY *CL 2/28/15 No violations on file — pop. 100
FARMERS DAUGHTER WATER SYS *CLOSED* No violations on file — pop. 100
DWR DELTA FIELD DIVISION-BANKS PUMP No violations on file — pop. 100 — serves COPPEROPOLIS
OROVILLE-WYANDOTTE IRRIG DIST No violations on file — pop. 100
SANDMOUND MUTUAL Open violation — pop. 100
BETHEL MARKET No violations on file — pop. 100
DELTA BAR AND GRILL No violations on file — pop. 100
ANGLERS SUBDIVISION 4 No violations on file — pop. 99
BELLA VISTA WATER SYS Open violation — pop. 93
NORTH AMERICAN REFRACTORIES - INACTIVE No violations on file — pop. 90
MACS OLD HOUSE No violations on file — pop. 90
EBRPD ROUND VALLEY WATER SYSTEM No violations on file — pop. 82
RONALD NUNN No violations on file — pop. 80
NEW LIFE MARINA No violations on file — pop. 80
BETHEL ISLAND GOLF COURSE & COUNTRY CLUB No violations on file — pop. 80
MARINA MOBILE MANOR No violations on file — pop. 75
CRUISER HAVEN MARINA No violations on file — pop. 75
BETHEL BAPTIST CHURCH No violations on file — pop. 75
BRIDGEHEAD CAFE No violations on file — pop. 75
OLD BORGES RANCH WATER SYS No violations on file — pop. 75
LAUNDERETTE WATER SYSTEM *CL 04 No violations on file — pop. 75
GOLF CLUB AT RODDY RANCH Older violation on record — pop. 75
EBRPD BLACK DIAMOND MINES No violations on file — pop. 74
KNIGHTSEN COMMUNITY WATER SYSTEM No violations on file — pop. 73
RAYNERS GROCERY SWS **CLOSED** No violations on file — pop. 70
TUGS No violations on file — pop. 70
SANDY POINT MOBILE HOME PARK Open violation — pop. 67
EBRPD LITTLE HILLS No violations on file — pop. 66
DOUBLETREE RANCH WATER SYSTEM No violations on file — pop. 66
MORAGA HEIGHTS MUTUAL WATER No violations on file — pop. 66
DAVIS CAMP *CL 10/08 No violations on file — pop. 65
BONNIE & CLYDES SALOON No violations on file — pop. 65
WAHL FAMILY WATER SYSTEM No violations on file — pop. 65
LITTORNO & PANFILI WATER SYSTEM No violations on file — pop. 60
ANGLER S RANCH #3 No violations on file — pop. 60
WILLOW PASS BUSSINESS PARK WATER SYSTEM No violations on file — pop. 60
BYRON INN No violations on file — pop. 60
EBRPD MORGAN TERRITORY No violations on file — pop. 57
MCAVOY YACHT HARBOR No violations on file — pop. 55
CSP CALIFORNIA STATE PARKS No violations on file — pop. 54
BETHEL MISSIONARY BAPTIST No violations on file — pop. 54
MILAN E WARD Older violation on record — pop. 50
BYRON UNITED METHODIST No violations on file — pop. 50
DUTCH SLOUGH WATER WORKS No violations on file — pop. 49
EBRPD OLD BRIONES REGIONAL PARK No violations on file — pop. 47
DELTA KIDS CENTER *CL 2/07 No violations on file — pop. 45
MARINE EMPORIUM RICHARDS YACHT No violations on file — pop. 45
HOLLAND RIVERSIDE MARINA No violations on file — pop. 45
BETHEL HARBOR No violations on file — pop. 45
CASA MEDANOS WATER SYSTEM No violations on file — pop. 45
BEACON WEST No violations on file — pop. 45
LONE TREE MEDICAL & DENTAL No violations on file — pop. 45
BAY STANDARDS No violations on file — pop. 41
BLACKWOOD & ELY No violations on file — pop. 40
HONOLULU GRILL *CL 10/07 No violations on file — pop. 40
EBRPD BEAR CREEK WATER SYSTEM No violations on file — pop. 35
PARK MARINA *CL 10/29/15 No violations on file — pop. 35
CECCHINI WATER No violations on file — pop. 35
BYRON AIRPORT No violations on file — pop. 35
WILLOWEST MARINA WS No violations on file — pop. 35
HERTZ WATER SYSTEM No violations on file — pop. 35
CARSON SWIM SCHOOL Older violation on record — pop. 35
ANCHOR MARINA No violations on file — pop. 35
BLACKHAWK WATER SERVICE No violations on file — pop. 33
COLONIA SANTA MARIA Open violation — pop. 32
WILCOX STATION RANCH No violations on file — pop. 31
BOLLINGER CANYON No violations on file — pop. 30
BETH BLASEY No violations on file — pop. 30
CASA DEL RIO WATER SYSTEM No violations on file — pop. 30
ALL STAR ACADEMY OF DANVILLE No violations on file — pop. 30
BRENTWOOD MARINA No violations on file — pop. 30
SUNSET MARINA No violations on file — pop. 30
LAST RESORT & MARINA LLC No violations on file — pop. 30
D ANNA YACHT CENTER *CL 2005 Older violation on record — pop. 30
RIVERVIEW MOTEL *CL 2007 No violations on file — pop. 30
SUES SWIM SCHOOL No violations on file — pop. 30
VALLEY ORCHARD MUTUAL WATER CO No violations on file — pop. 30
099 152 022 PG&E LOS MEDANOS No violations on file — pop. 28
FRANK & CAROLE KARAGLANIS Older violation on record — pop. 28
WILDWOOD ACRES RESORT No violations on file — pop. 28
010 050 003 No violations on file — pop. 26
SEYMOUR PAUL PROCTOR No violations on file — pop. 25
JAMES A MCGRATH No violations on file — pop. 25
SAVERS SWS No violations on file — pop. 25
DUDLEY YOUNG No violations on file — pop. 25
SMITH & HAGER WATER SYSTEM No violations on file — pop. 25
MT VIEW FOOD CENTER Older violation on record — pop. 25
GARY LARSEN No violations on file — pop. 25
MT DIABLO STATE PARK No violations on file — pop. 25
BOUNDARY OAKS TENNIS CORP No violations on file — pop. 25
MASS PHEASANT CLUB No violations on file — pop. 25
MOTORCYCLE RECREATION No violations on file — pop. 25
CSP LAKE OROVILLE-SPILLWAY No violations on file — pop. 25 — serves NC SPILLWAY LAU
EVERGREEN MOBILEHOME PARK No violations on file — pop. 25
BRENTWOOD MISSIONARY BAPTIST No violations on file — pop. 25
LOS VAQUEROS INTERPRETIVE CENTER No violations on file — pop. 25
BYRON ROADHOUSE No violations on file — pop. 25
MARIN FOOD SPECIALTIES Older violation on record — pop. 25
TESS FARM MARKET No violations on file — pop. 25 — serves BRENTWOOD
BLUE TIP TRAILER PARK WATER No violations on file — pop. 24
VALLEY ORCHARD MUTUAL WATER SYSTEM No violations on file — pop. 24
LAZY M MARINA No violations on file — pop. 23
CASTLEROCK WATER SYS No violations on file — pop. 22
DELTA WAVES No violations on file — pop. 22
LOUIS & LUPE MADRIGAL No violations on file — pop. 20
RIVERVIEW MARINA SWS No violations on file — pop. 20
VILLA DE GUADALUPE Older violation on record — pop. 20
BRENTWOOD CREEK FARM Older violation on record — pop. 18
CORNER CLUB Older violation on record — pop. 15
LEEMA ROAD WATER SYSTEM No violations on file — pop. 15
MORRISON RANCH No violations on file — pop. 10
BYRON HOLWAY WATER SYSTEM No violations on file — pop. 10
CANYON WATER BROTHERS No violations on file — pop. 5
NAGLE APARTMENTS No violations on file — pop. 4
YOSEMITE WEST No violations on file — pop. 3
BLUE GOOSE PROPERTY No violations on file — pop. 1
RANDALL-BOLD WATER TREATMENT PLANT No violations on file — pop. 1
SANTIAGO ISLAND VILLAGE No violations on file — pop. 0
OWID-COMMUNITY LINE No violations on file — pop. 0 — serves COMMUNITY LINE
MARK & DEBORAH REISBECK No violations on file — pop. 0
CCWD/BRENTWOOD WTP No violations on file — pop. 0
ORIN ALLEN YOUTH REHAB FACILITY No violations on file — pop. 0

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What is TTHM? Understanding EPA Violation Status Is Chromium-6 Dangerous? Whole-House vs. Under-Sink Filtration Lead and Copper in Drinking Water What is PFAS? Arsenic and Uranium Explained Nitrate and Fluoride Explained Water Hardness, pH, and Turbidity What is Coliform Bacteria?

Contra Costa County, CA Water Quality Report

Violations on file

Contaminants found

Browse by city

Individual water providers