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Results for Mono County, CA

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

Quick answer: Mono County has 127 water providers profiled, sorted by population served.

Nitrate
Lead Summary
Copper Summary
Lithium
Totalhaloaceticacids (HAA5)
TTHM
Chloroform
Bromodichloromethane
Dichloroaceticacid
Trichloroaceticacid
Iron
Arsenic
Manganese
Sodium
Calcium
Alkalinity, Total
Alkalinity, Bicarbonate
Hardness, Total (ASCACO3)
TDS
Sulfate
Turbidity
pH
Conductivity (at 25°C)
Dibromoaceticacid
Dibromochloromethane
Monochloroaceticacid
Combined Uranium
Gross Alpha Particle Activity
Aluminum
Magnesium
Lead
Copper, Free
Chromium, Hex
Color
Nitrate-Nitrite
Bromoform
Potassium
Zinc
Chloride
Barium
Fluoride
Gross Beta Particle Activity

Violations on file

Fluoride

Older/archived health-based violation

Found at 1 of 127 providers

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

Lead And Copper Rule Revisions

Currently open health violation

Found at 5 of 127 providers

Surface Water Treatment Rule

Older/archived health-based violation

Found at 1 of 127 providers

Arsenic

Older/archived health-based violation

Found at 1 of 127 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.

Coliform (TCR)

Older/archived health-based violation

Found at 2 of 127 providers

Nitrate

Older/archived health-based violation

Found at 1 of 127 providers

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

Contaminants found

Metals

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

Lead Summary

Detected: 0.0094 mg/L (ppm)

Found at 21 providers

Copper Summary

Detected: 3.3 mg/L (ppm)

Found at 4 providers

Iron

Detected: 130 UG/L (ppb)

Found at 3 providers

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

Arsenic

Detected: 29 UG/L (ppb)

Found at 5 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.

Manganese

Detected: 540 UG/L (ppb)

Found at 2 providers

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

Combined Uranium

Detected: 38 PCI/L

Found at 3 providers

A naturally occurring radioactive metal. Long-term exposure above the legal limit is associated with kidney effects and increased cancer risk.

Aluminum

Detected: 130 UG/L (ppb)

Found at 2 providers

Lead

Detected: 4.9 UG/L (ppb)

Found at 4 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.

Copper, Free

Detected: 330 UG/L (ppb)

Found at 4 providers

Chromium, Hex

Detected: 2.1 UG/L (ppb)

Found at 6 providers

Zinc

Detected: 35 UG/L (ppb)

Found at 2 providers

Barium

Detected: 120 UG/L (ppb)

Found at 2 providers

Disinfection Byproducts

Formed when chlorine used to disinfect water reacts with organic matter

Totalhaloaceticacids (HAA5)

Detected: 9.3 UG/L (ppb)

Found at 2 providers

TTHM

Detected: 16 UG/L (ppb)

Found at 3 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.

Chloroform

Detected: 15 UG/L (ppb)

Found at 3 providers

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

Bromodichloromethane

Detected: 0.85 UG/L (ppb)

Found at 4 providers

Dibromochloromethane

Detected: 1.3 UG/L (ppb)

Found at 2 providers

Bromoform

Detected: 1.2 UG/L (ppb)

9/10/2025

Inorganics

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

Nitrate

Detected: 7.3 MG/L (ppm)

Found at 31 providers

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

Sulfate

Detected: 8.3 MG/L (ppm)

Found at 4 providers

Nitrate-Nitrite

Detected: 1.94 MG/L (ppm)

Found at 11 providers

Chloride

Detected: 20 MG/L (ppm)

Found at 2 providers

Fluoride

Detected: 1.7 MG/L (ppm)

10/7/2025

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

Minerals

Everyday minerals that mainly affect taste and water hardness

Sodium

Detected: 110 MG/L (ppm)

Found at 4 providers

Calcium

Detected: 73 MG/L (ppm)

Found at 4 providers

Magnesium

Detected: 28 MG/L (ppm)

Found at 3 providers

Potassium

Detected: 5.2 MG/L (ppm)

Found at 2 providers

Properties

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

Hardness, Total (ASCACO3)

Detected: 300 MG/L (ppm)

Found at 4 providers

Detected: 7.75 PH

Found at 4 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: 41.9 PCI/L

Found at 5 providers

PFAS & Emerging Contaminants

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

Lithium

Detected: 96.7 µg/L (ppb)

Found at 2 providers

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

Calculated Parameters

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

Alkalinity, Bicarbonate

Detected: 120 MG/L (ppm)

Found at 4 providers

Other

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

Dichloroaceticacid

Detected: 4.4 UG/L (ppb)

Found at 2 providers

Trichloroaceticacid

Detected: 4.9 UG/L (ppb)

Found at 2 providers

Alkalinity, Total

Detected: 120 MG/L (ppm)

Found at 4 providers

TDS

Detected: 160 MG/L (ppm)

Found at 4 providers

Turbidity

Detected: 0.3 NTU

Found at 3 providers

A measure of water cloudiness from suspended particles.

Conductivity (at 25°C)

Detected: 270 UMHO/CM

Found at 4 providers

Dibromoaceticacid

Detected: 1.7 UG/L (ppb)

Found at 2 providers

Monochloroaceticacid

Detected: 2 UG/L (ppb)

9/16/2025

Color

Detected: 1 UNITS

2/26/2025

Gross Beta Particle Activity

Detected: 13 PCI/L

7/21/2025

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
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
Lithium	Partial	Yes*	Partial
Dichloroaceticacid	Partial	Yes	Partial
Trichloroaceticacid	Partial	Yes	Partial
Iron	Partial	Yes	Partial
Manganese	Partial	Yes	Partial
Alkalinity, Total	Partial	Yes	Partial
TDS	Partial	Yes	Partial
Sulfate	Partial	Yes	Partial
Conductivity (at 25°C)	Partial	Yes	Partial
Dibromoaceticacid	Partial	Yes	Partial
Monochloroaceticacid	Partial	Yes	Partial
Combined Uranium	Partial	Yes	Partial
Aluminum	Partial	Yes	Partial
Copper, Free	Partial	Yes	Partial
Chromium, Hex	Partial	Yes	Partial
Color	Partial	Yes	Partial
Nitrate-Nitrite	Partial	Yes	Partial
Zinc	Partial	Yes	Partial
Chloride	Partial	Yes	Partial
Barium	Partial	Yes	Partial
Fluoride	Partial	Yes	Partial
Gross Beta Particle Activity	Partial	Yes	Partial
Coliform Bacteria (indicator)	No	Yes	No
Sodium	No	Partial	No
Calcium	No	Partial	No
Alkalinity, Bicarbonate	No	No	No
Hardness, Total (ASCACO3)	No	No	No
pH	No	No	No
Gross Alpha Particle Activity	No	No	No
Magnesium	No	Partial	No
Potassium	No	Partial	No

Individual water providers

ROBINSON CREEK CAMPGROUND No violations on file — pop. 50,562
MAMMOTH CWD No violations on file — pop. 8,234
MAMMOTH MOUNTAIN SKI AREA - OUTPOST 14 No violations on file — pop. 7,736
TRUMBULL LAKE CAMPGROUND No violations on file — pop. 7,423
JUNE LAKE PUD - DOWN CANYON Open violation — pop. 2,810
JUNE LAKE PUD VILLAGE Open violation — pop. 2,763
BOOTLEG CAMPGROUND No violations on file — pop. 2,467
CHRIS FLAT CAMPGROUND No violations on file — pop. 1,585
LEAVITT CAMPGROUND No violations on file — pop. 1,405
USMC/MTN WARFARE TRNG CTR - BRIDGEPORT No violations on file — pop. 1,200
MAMMOTH LAKES BASIN No violations on file — pop. 1,000
EAST FORK CAMPGROUND No violations on file — pop. 750

LEE VINING PUBLIC UTILITY DISTRICT No violations on file — pop. 672
FRENCH CAMP CAMPGROUND No violations on file — pop. 600
BRIDGEPORT PUD Open violation — pop. 524
JUNE MOUNTAIN SKI AREA - UPPER No violations on file — pop. 514
JUNE MOUNTAIN SKI AREA - LOWER No violations on file — pop. 514
MOUNTAIN MEADOWS MWC No violations on file — pop. 505
ANNETT'S MONO VILLAGE No violations on file — pop. 500
TWIN LAKES FAMILY CAMPGROUND 2 No violations on file — pop. 470
CONVICT LAKE CAMPGROUND No violations on file — pop. 440
USMC - HOUSING COLEVILLE No violations on file — pop. 424
CONWAY RANCH No violations on file — pop. 375
BIG BEND CAMPGROUND No violations on file — pop. 345
TWIN LAKES ENTERPRISES No violations on file — pop. 325
SADDLEBAG LAKE CAMPGROUND No violations on file — pop. 325
LOWER ROCK CREEK MUTUAL WATER CO. Open violation — pop. 310
CAL TRANS - CRESTVIEW REST AREA No violations on file — pop. 300
CSP - BODIE SHP No violations on file — pop. 271
CROWLEY LAKE TRAILER PARK Open violation — pop. 230
COLEVILLE HIGH SCHOOL No violations on file — pop. 216
DONALD MAES No violations on file — pop. 200
BRUCE CLARK WATER SYSTEM No violations on file — pop. 200
USFS LEE VINING RANGER STATION No violations on file — pop. 200
TUFF CAMPGROUND No violations on file — pop. 180
CROWLEY LAKE MUTUAL WATER COMPANY Older violation on record — pop. 175
MCGEE CREEK CAMPGROUND No violations on file — pop. 168
TOM'S PLACE No violations on file — pop. 156
BIG MEADOW CAMPGROUND No violations on file — pop. 154
YMCA CAMP HIGH SIERRA No violations on file — pop. 150
BIRCHIM COMMUNITY SERVICE DISTRICT No violations on file — pop. 150
MCGEE CREEK MOBILE HOME PARK No violations on file — pop. 146
WHITE MOUNTAIN MUTUAL WATER COMPANY No violations on file — pop. 142
GRANT LAKE MARINA No violations on file — pop. 130
TOPAZ LAKE RV PARK No violations on file — pop. 127
PINE GROVE CAMPGROUND No violations on file — pop. 120
HUNEWILL GUEST RANCH No violations on file — pop. 115
LAKE MARY STORE No violations on file — pop. 100
USFS - AERIE CRAG No violations on file — pop. 100
GRANT OVERLOOK CAMPGROUND No violations on file — pop. 100
WHITE MOUNTAINS BIBLE CHAPEL No violations on file — pop. 100
KILBURN ROBY No violations on file — pop. 100
AERIE CRAG No violations on file — pop. 100
GRANT OVERLOOK No violations on file — pop. 100
LAKE MARY STORE No violations on file — pop. 100
POKONOBE LODGE RESTAURANT/STORE No violations on file — pop. 100
LOG CABIN WILDERNESS CAMP No violations on file — pop. 100
CROWLEY LAKE GENERAL STORE No violations on file — pop. 100
HUNEWILL'S DOC AND AL'S RESORT No violations on file — pop. 100
TWIN LAKES RESORT No violations on file — pop. 100
BRIDGEPORT RESERVOIR MARINA AND CG No violations on file — pop. 90
WHEELER CREST CSD No violations on file — pop. 86
SIERRA EAST HOA Older violation on record — pop. 84
CRYSTAL CRAG WATER & DEVELOPMENT ASSOC. No violations on file — pop. 75
WOODS LODGE No violations on file — pop. 75
SAGE AND SAND TRAILER PARK Older violation on record — pop. 70
QUALITY TRAILER PARK No violations on file — pop. 70
OBSIDIAN CAMPGROUND 2 No violations on file — pop. 70
LUNDY MUTUAL WATER COMPANY No violations on file — pop. 70
LUNDY LAKE RESORT No violations on file — pop. 70
ELLERY LAKE CAMPGROUND No violations on file — pop. 70
TIOGA GAS MART No violations on file — pop. 69
BROWN'S OWENS RIVER CAMPGROUND No violations on file — pop. 66
COLD WATER CANYON MWC No violations on file — pop. 65
TIOGA LAKE CAMPGROUND No violations on file — pop. 65
VIRGINIA LAKES MUTUAL WATER CO. No violations on file — pop. 51
MARTIN'S TRAILER PARK 1 No violations on file — pop. 50
WHEELER GUARD STATION No violations on file — pop. 50
UCLA CROOKEDCREEK RESEARCH STA No violations on file — pop. 50
PINE GLADE ASSOCIATION No violations on file — pop. 50
CROWLEY LAKE CAMPGROUND (BLM) No violations on file — pop. 50
SAN GABRIEL VALLEY FAMILY CENTER No violations on file — pop. 50
WHITMORE POOL No violations on file — pop. 50
VIRGINIA CREEK SETTLEMENT No violations on file — pop. 47
TWIN LAKES STORE No violations on file — pop. 46
CROWLEY LAKE FISH CAMP No violations on file — pop. 46
CHALFANT VALLEY WEST M.W.C. No violations on file — pop. 45
CROWLEY LAKE CAMPLAND No violations on file — pop. 45
MOUNTAIN GATE LODGE 2 No violations on file — pop. 40
TIOGA LODGE Older violation on record — pop. 38
ALPER'S OWENS RIVER RANCH 2 No violations on file — pop. 35
ARCULARIUS RANCH No violations on file — pop. 35
WHITMORE BALLFIELDS No violations on file — pop. 30
MCGEE CREEK LODGE No violations on file — pop. 29
LATIN MARKET 2 No violations on file — pop. 27
HOT CREEK RANCH No violations on file — pop. 27
EDNA BEAMAN ELEMENTARY SCHOOL Older violation on record — pop. 26
DAVIS' HIGH COUNTRY CAFE No violations on file — pop. 25
GLEN ROWLEY No violations on file — pop. 25
MAMMOTH SHERIFF SUBSTATION 3 No violations on file — pop. 25
BENTON FIRE STATION No violations on file — pop. 25
HAMMERBACHERS No violations on file — pop. 25
BRIDGEPORT RESERVOIR BOAT LANDING No violations on file — pop. 25
COACHWHIP CAFE No violations on file — pop. 25
BENTON STATION No violations on file — pop. 25
WALKER RV PARK No violations on file — pop. 25
MOUNTAIN VIEW BARBEQUE No violations on file — pop. 25
MEADOWCLIFF LODGE & COLEVILLE/WALKER KOA No violations on file — pop. 25
WALKER COMMUNITY HALL AND PARK No violations on file — pop. 25
WALKER BURGER No violations on file — pop. 25
MONO INN No violations on file — pop. 25
ROCK CREEK LODGE No violations on file — pop. 25
MONO LAKE COUNTY PARK No violations on file — pop. 25
WALKER COUNTRY STORE B.C.D.C. No violations on file — pop. 25
SIERRA BUSINESS PARK OWNER'S ASSOCIATION No violations on file — pop. 25
CROWLEY LAKE PARK No violations on file — pop. 25
CHALFANT COMMUNITY CENTER No violations on file — pop. 25
BENTON COMMUNITY CENTER No violations on file — pop. 25
HOT CREEK HATCHERY No violations on file — pop. 24
TOPAZ MOBILE HOME PARK No violations on file — pop. 22
CONWAY SUMMIT FIRE STATION No violations on file — pop. 20
PARADISE SHORES RV PARK No violations on file — pop. 20
MAMMOTH YOSEMITE AIRPORT No violations on file — pop. 13
JUNE LAKE PRESCHOOL No violations on file — pop. 10
WILLOW SPRINGS RESORT No violations on file — pop. 9
CAMP ANTELOPE No violations on file — pop. 0
WHEELER CREST CSD 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?

Mono County, CA Water Quality Report

Violations on file

Contaminants found

Individual water providers