Water Quality Lookup / California / Lassen County

EPA SDWIS · Lassen County, California · 152 providers profiled

Lassen County, CA Water Quality Report

Lassen County is served by 152 major public water systems on file with the EPA.

Data current as of July 2026

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Results for Lassen County, CA

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

Quick answer: Lassen County has 152 water providers profiled, sorted by population served.

Violations on file

Arsenic

Older/archived health-based violation

Found at 2 of 152 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.

Fluoride

Older/archived health-based violation

Found at 1 of 152 providers

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

Nitrate

Older/archived health-based violation

Found at 1 of 152 providers

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

Coliform (TCR)

Older/archived health-based violation

Found at 7 of 152 providers

Lead And Copper Rule Revisions

Currently open health violation

Found at 4 of 152 providers

Stage 1 Disinfectants And Disinfection Byproducts Rule

Older/archived health-based violation

Found at 1 of 152 providers

Contaminants found

Metals

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

Lead Summary

Detected: 0.005 mg/L (ppm)

Found at 32 providers

Copper Summary

Detected: 3.385 mg/L (ppm)

06/30/2019

Copper, Free

Detected: 320 UG/L (ppb)

Found at 8 providers

Chromium, Hex

Detected: 2.7 UG/L (ppb)

Found at 14 providers

Manganese

Detected: 510 UG/L (ppb)

Found at 4 providers

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

Combined Uranium

Detected: 9.7 PCI/L

Found at 4 providers

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

Zinc

Detected: 20 UG/L (ppb)

1/29/2025

Iron

Detected: 3730 UG/L (ppb)

Found at 4 providers

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

Lead

Detected: 1 UG/L (ppb)

Found at 2 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.

Barium

Detected: 57 UG/L (ppb)

4/21/2025

Arsenic

Detected: 29 UG/L (ppb)

Found at 4 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.

Disinfection Byproducts

Formed when chlorine used to disinfect water reacts with organic matter

Totalhaloaceticacids (HAA5)

Detected: 3.5 UG/L (ppb)

8/6/2025

TTHM

Detected: 26.9 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: 2 UG/L (ppb)

Found at 2 providers

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

Bromoform

Detected: 12.1 UG/L (ppb)

Found at 4 providers

Bromodichloromethane

Detected: 3.6 UG/L (ppb)

Found at 3 providers

Dibromochloromethane

Detected: 9.6 UG/L (ppb)

Found at 3 providers

Inorganics

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

Nitrate

Detected: 7.4 MG/L (ppm)

Found at 33 providers

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

Sulfate

Detected: 7.9 MG/L (ppm)

Found at 2 providers

Chloride

Detected: 5 MG/L (ppm)

Found at 2 providers

Nitrate-Nitrite

Detected: 0.5 MG/L (ppm)

1/29/2025

Nitrite

Detected: 0.55 MG/L (ppm)

8/20/2025

Fluoride

Detected: 0.2 MG/L (ppm)

4/23/2025

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

Minerals

Everyday minerals that mainly affect taste and water hardness

Magnesium

Detected: 15 MG/L (ppm)

Found at 4 providers

Potassium

Detected: 4 MG/L (ppm)

Found at 2 providers

Sodium

Detected: 60 MG/L (ppm)

Found at 3 providers

Calcium

Detected: 34 MG/L (ppm)

Found at 4 providers

Properties

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

Gross Alpha Particle Activity

Detected: 13.7 PCI/L

Found at 7 providers

Langelier Index (pH(s))

Detected: -0.1 LANG

Found at 2 providers

Hardness, Total (ASCACO3)

Detected: 150 MG/L (ppm)

Found at 4 providers

pH, Field

Detected: 8 PH

Found at 3 providers

pH

Detected: 6.42 PH

5/2/2025

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

PFAS & Emerging Contaminants

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

Lithium

Detected: 23.9 µg/L (ppb)

8/5/2024

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

Trichloroethylene

Detected: 4.8 UG/L (ppb)

10/1/2025

Tetrachloroethylene

Detected: 6.1 UG/L (ppb)

10/1/2025

Cis-1, 2-Dichloroethylene

Detected: 6.7 UG/L (ppb)

10/1/2025

Petroleum Compounds

Substances associated with fuel or petroleum contamination

Toluene

Detected: 3.1 UG/L (ppb)

8/6/2025

Benzene

Detected: 0.74 UG/L (ppb)

5/28/2025

Calculated Parameters

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

Alkalinity, Bicarbonate

Detected: 170 MG/L (ppm)

Found at 3 providers

Other

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

Methyltert-Butylether

Detected: 18 UG/L (ppb)

8/6/2025

Adsorbableorganicfluorine

Detected: 2700 NG/L (ppt)

Found at 3 providers

Aggressive Index

Detected: 11.7 AGGR

Found at 2 providers

Alkalinity, Total

Detected: 140 MG/L (ppm)

Found at 4 providers

TDS

Detected: 240 MG/L (ppm)

Found at 3 providers

Turbidity

Detected: 45 NTU

Found at 3 providers

A measure of water cloudiness from suspended particles.

Conductivity (at 25°C)

Detected: 790 UMHO/CM

Found at 4 providers

Radium-228

Detected: 0.562 PCI/L

Found at 5 providers

Color

Detected: 110 UNITS

Found at 2 providers

Dichloroaceticacid

Detected: 1.2 UG/L (ppb)

Found at 2 providers

Trichloroaceticacid

Detected: 1.1 UG/L (ppb)

5/28/2025

Dibromoaceticacid

Detected: 3 UG/L (ppb)

Found at 2 providers

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
Copper, Free	Partial	Yes	Partial
Chromium, Hex	Partial	Yes	Partial
Methyltert-Butylether	Partial	Yes	Partial
Adsorbableorganicfluorine	Partial	Yes	Partial
Manganese	Partial	Yes	Partial
Combined Uranium	Partial	Yes	Partial
Aggressive Index	Partial	Yes	Partial
Alkalinity, Total	Partial	Yes	Partial
TDS	Partial	Yes	Partial
Sulfate	Partial	Yes	Partial
Chloride	Partial	Yes	Partial
Nitrate-Nitrite	Partial	Yes	Partial
Zinc	Partial	Yes	Partial
Conductivity (at 25°C)	Partial	Yes	Partial
Iron	Partial	Yes	Partial
Barium	Partial	Yes	Partial
Color	Partial	Yes	Partial
Dichloroaceticacid	Partial	Yes	Partial
Trichloroaceticacid	Partial	Yes	Partial
Dibromoaceticacid	Partial	Yes	Partial
Nitrite	Partial	Yes	Partial
Lithium	Partial	Yes*	Partial
Fluoride	Partial	Yes	Partial
Coliform Bacteria (indicator)	No	Yes	No
Gross Alpha Particle Activity	No	No	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

Browse by city

Individual water providers

CITY OF SUSANVILLE No violations on file — pop. 7,811 — serves SUSANVILLE
CDCR-HIGH DESERT STATE PRISON No violations on file — pop. 3,857
HERLONG PUBLIC UTILITY DISTRICT No violations on file — pop. 2,114
WESTWOOD C.S.D. No violations on file — pop. 1,662
CALIFORNIA CORRECTIONAL CENTER No violations on file — pop. 1,550
CALIFORNIA CONSERVATION CENTER No violations on file — pop. 1,550
LASSEN COMMUNITY COLLEGE DIST. Older violation on record — pop. 1,380
SIERRA ARMY DEPOT No violations on file — pop. 1,200
LEAVITT LAKE CSD No violations on file — pop. 950
LAKE FOREST MUTUAL W.C. No violations on file — pop. 565
WEST PATTON VILLAGE WATER No violations on file — pop. 465
WEST PATTON VILLAGE CSD Older violation on record — pop. 465

LASSEN COUNTY WATER WORKS DISTRICT #1 No violations on file — pop. 450
HERLONG HOMES WATER SYSTEM No violations on file — pop. 425
CLEAR CREEK CSD-WESTWOOD No violations on file — pop. 400
JANESVILLE ELEMENTARY SCHOOL No violations on file — pop. 400
CALTRANS-HONEY LAKE SRRA No violations on file — pop. 350
SPAULDING EAGLE LAKE MWC No violations on file — pop. 317
SUSAN HILLS ESTATES WC No violations on file — pop. 252
SHAFFER ELEMENTARY SCHOOL No violations on file — pop. 250
DOLLAR GENERAL JANESVILLE No violations on file — pop. 250
JOHNSTONVILLE ELEMENTARY SCHOOL No violations on file — pop. 230
RICHMOND ELEMENTARY SCHOOL No violations on file — pop. 221
LNF-EAGLE LAKE CAMPGROUNDS No violations on file — pop. 200
LONG VALLEY CHARTER SCHOOL No violations on file — pop. 196
BLUE LAKE YOUTH CAMP No violations on file — pop. 150
SUSAN RIVER PARK WATER CO. No violations on file — pop. 140
JACK'S VALLEY RESTSTOP, CALTRANS No violations on file — pop. 125
MOUNTAIN VALLEY LATTER-DAY SAINTS CHURCH No violations on file — pop. 110
CAL FIRE-INTERMOUNTAIN CONSERVATION CAMP No violations on file — pop. 108
YUBA PASS CAMPGROUND No violations on file — pop. 100
HACIENDA FAMILY RESTAURANT No violations on file — pop. 100
NEIL'S MERCANTILE Older violation on record — pop. 100
CINDERCONE SKATELAND No violations on file — pop. 100
EAGLE LAKE MARINA No violations on file — pop. 100
LNF-BOGARD WORK CENTER/CAL TRANS SRRA No violations on file — pop. 100
INTERMOUNTAIN CONSERVATION CAM No violations on file — pop. 87
INTERMOUNTAIN No violations on file — pop. 87
CALTRANS-SCERET VALLEY RESTSTOP No violations on file — pop. 85
EAGLE NEST HOMEOWNERS' ASSOCIATION No violations on file — pop. 84
PINEVIEW MOBILE HOME PARK Open violation — pop. 80
DOLLAR GENERAL DOYLE No violations on file — pop. 80
WILLOW CREEK GUARD STA & CG No violations on file — pop. 78
LITTLE VALLEY CSD Open violation — pop. 70
EAGLE LAKE RV PARK No violations on file — pop. 68
HERLONG MOBILEHOME PARK Older violation on record — pop. 62
LASSEN MOBILE HOME PARK No violations on file — pop. 62
LAHONTAN HEIGHTS HOME. ASSOC. No violations on file — pop. 56
SIERRA CASCADE NURSERY No violations on file — pop. 55
DIAMOND MOUNTAIN GOLF CLUB No violations on file — pop. 54
HONEY LAKE MARKET No violations on file — pop. 50
POINT HORIZON INSTITUTE No violations on file — pop. 48
EAGLE LAKE RANGER DISTRICT No violations on file — pop. 45
WILLOW CREEK CAMPGROUND No violations on file — pop. 45
JANESVILLE CHRISTIAN SCHOOL No violations on file — pop. 44
TERMO STORE WATER SYSTEM No violations on file — pop. 40
BUTTE CREEK CAMPGROUND No violations on file — pop. 40
LNF-EAGLE LAKE RANGER STATION Open violation — pop. 40
JOHNSTONVILLE WATER SYSTEM Open violation — pop. 40
CLEAR CREEK LATTER DAY SAINTS CHURCH No violations on file — pop. 40
HAIL MOTEL/FRANKIE'S CAFE No violations on file — pop. 35 — serves URBAN BAKERSFIE
WINJE'S EMPORIUM No violations on file — pop. 35
EAGLE LAKE CAMPGROUND, BLM No violations on file — pop. 35
LASSEN CO. OFF. OF EDUCATION No violations on file — pop. 32
CCS - THE STRAND No violations on file — pop. 30
THE MEADOWS No violations on file — pop. 30
BIG VALLEY MEDICAL CENTER - INACTIVE Older violation on record — pop. 30
WAYSIDE INN MARKET Older violation on record — pop. 30
DOYLE PAYLESS SHELL No violations on file — pop. 30
CITIZENS COMMUNICATIONS No violations on file — pop. 27
DAYS END RV PARK No violations on file — pop. 27
MOUNTAIN JEWELL RANCH No violations on file — pop. 26
R HOUSE RESTAURANT No violations on file — pop. 26
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
USFS LASSEN NF No violations on file — pop. 25
VALLEY HIGH VILLA WATER SYSTEM No violations on file — pop. 25
WHITE HOUSE WEST No violations on file — pop. 25
UNION PACIFIC RAILROAD No violations on file — pop. 25
DFG-DAKIN UNIT No violations on file — pop. 25
SEAWARD MCKEE DDS No violations on file — pop. 25
JAE MOTEL No violations on file — pop. 25
OLIVER'S CAFE No violations on file — pop. 25
ROQUE'S RESTRURANT WATER SYS No violations on file — pop. 25
GATEWAY PLAZA WATER SYSTEM (JIMBOB'S) No violations on file — pop. 25
ALLEN'S GIFT SHOP & SNACK BAR No violations on file — pop. 25
EAGLE LAKE GENERAL STORE No violations on file — pop. 25
GALLATIN CG, LASSEN NF No violations on file — pop. 25
STONES LANDING No violations on file — pop. 25
PNF-LAUFMAN ADMIN. SITE Older violation on record — pop. 25
H.L. POWER COMPANY No violations on file — pop. 25
HALLELUJAH JUNCTION MARKET No violations on file — pop. 25
JANESVILLE FIRE HALL No violations on file — pop. 25
HONEY LAKE CAMPGROUND Older violation on record — pop. 25
JOHNSTONVILLE QUALITY FOODS No violations on file — pop. 25
MOUNTAIN MEADOW RANCH No violations on file — pop. 25
THE MARK No violations on file — pop. 25
LASSEN RV PARK & CAMPGROUND No violations on file — pop. 25
LAKEVIEW INN AND EAGLE LAKE BAR & GRILL No violations on file — pop. 25
HIGH DESERT ADULT & TEEN CHALLENGE No violations on file — pop. 25 — serves SUSANVILLE
MDF-WILLOW CREEK CG No violations on file — pop. 25
PIZZA FACTORY JANESVILLE No violations on file — pop. 25
JANESVILLE CHEVRON No violations on file — pop. 25
ARTISAN COFFEE No violations on file — pop. 25
SUPER Y MARKET AND VILLA MONTE MOTEL No violations on file — pop. 25
LEAVITT LAKE MARKET No violations on file — pop. 25
MARINER'S RESORT Older violation on record — pop. 25
WENDEL WATER SYSTEM No violations on file — pop. 24
COUNTRY CLUB COURTS WATER SYSTEM No violations on file — pop. 24
WOOD N PEG RANCH No violations on file — pop. 22
ALMANOR LAKE ESTATES MWC No violations on file — pop. 18
CRATER LAKE CG, LASSEN NF No violations on file — pop. 16
HONEY LAKE RANCH No violations on file — pop. 15
FLEMING UNIT, CA DEPT. OF FISH & GAME No violations on file — pop. 15
BOGARD CG, LASSEN NF No violations on file — pop. 15
MCDONALD WOOD PRODUCTS No violations on file — pop. 8
GRASSHOPPER FIRE STATION, CDF No violations on file — pop. 7
JANESVILLE SHCOOL No violations on file — pop. 6
RAM HORN SPRING CAMPGROUND, BLM No violations on file — pop. 1
BOGARD WORK CENTER, LASSEN NF No violations on file — pop. 1
BAR S No violations on file — pop. 1
ROXI PECONOM CG, LASSEN NF No violations on file — pop. 1
HEARD'S MARKET No violations on file — pop. 0 — serves URBAN BAKERSFIE
TREAT S CAFE Older violation on record — pop. 0
CALTRANS-ADIN MAINTENANCE STATION No violations on file — pop. 0
GATEWAY MARKET/TRAIL'S END DINER No violations on file — pop. 0
LASSEN FOREST PRODUCTS No violations on file — pop. 0
CA CORRECTIONAL CENTER Older violation on record — 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?