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Results for Colusa County, CA

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

Quick answer: Colusa County has 67 water providers profiled, sorted by population served.

Nitrate
Lead Summary
TTHM
Chloroform
Bromoform
Bromodichloromethane
Dibromochloromethane
Dibromoaceticacid
Lead
Copper, Free
Adsorbableorganicfluorine
Chromium, Hex
Arsenic
Manganese
Fluoride
Lithium
Odor
Iron
Radium-228
Totalhaloaceticacids (HAA5)
Sodium
Alkalinity, Total
Alkalinity, Bicarbonate
pH

Violations on file

Arsenic

Older/archived health-based violation

Found at 1 of 67 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: 0.02 mg/L (ppm)

Found at 19 providers

Lead

Detected: 1.64 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.

Copper, Free

Detected: 197 UG/L (ppb)

Found at 3 providers

Chromium, Hex

Detected: 26 UG/L (ppb)

Found at 4 providers

Arsenic

Detected: 23.7 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.

Manganese

Detected: 380 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.

Iron

Detected: 59.7 UG/L (ppb)

10/15/2025

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

Disinfection Byproducts

Formed when chlorine used to disinfect water reacts with organic matter

TTHM

Detected: 35 UG/L (ppb)

Found at 5 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: 7.4 UG/L (ppb)

Found at 4 providers

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

Bromoform

Detected: 18 UG/L (ppb)

Found at 4 providers

Bromodichloromethane

Detected: 7 UG/L (ppb)

Found at 4 providers

Dibromochloromethane

Detected: 9 UG/L (ppb)

Found at 4 providers

Totalhaloaceticacids (HAA5)

Detected: 1.1 UG/L (ppb)

8/19/2025

Inorganics

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

Nitrate

Detected: 5 MG/L (ppm)

Found at 9 providers

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

Fluoride

Detected: 0.2 MG/L (ppm)

7/24/2025

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

Minerals

Everyday minerals that mainly affect taste and water hardness

Sodium

Detected: 120 MG/L (ppm)

10/21/2025

Properties

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

Detected: 7.93 PH

10/21/2025

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: 41.9 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: 260 MG/L (ppm)

10/21/2025

Other

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

Dibromoaceticacid

Detected: 2 UG/L (ppb)

Found at 2 providers

Adsorbableorganicfluorine

Detected: 880 NG/L (ppt)

2/3/2025

Odor

Detected: 7 TON

9/4/2025

Radium-228

Detected: 0.881 PCI/L

6/25/2025

Alkalinity, Total

Detected: 260 MG/L (ppm)

10/21/2025

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
Dibromoaceticacid	Partial	Yes	Partial
Copper, Free	Partial	Yes	Partial
Adsorbableorganicfluorine	Partial	Yes	Partial
Chromium, Hex	Partial	Yes	Partial
Manganese	Partial	Yes	Partial
Fluoride	Partial	Yes	Partial
Lithium	Partial	Yes*	Partial
Odor	Partial	Yes	Partial
Iron	Partial	Yes	Partial
Alkalinity, Total	Partial	Yes	Partial
Coliform Bacteria (indicator)	No	Yes	No
Sodium	No	Partial	No
Alkalinity, Bicarbonate	No	No	No
pH	No	No	No

Browse by city

Individual water providers

CALTRANS-MAXWELL RESTSTOPS No violations on file — pop. 15,000
CITY OF COLUSA No violations on file — pop. 6,447 — serves COLUSA
CITY OF WILLIAMS No violations on file — pop. 5,538 — serves WILLIAMS
ARBUCKLE PUBLIC UTILITY DISTRICT No violations on file — pop. 2,778
MAXWELL PUBLIC UTILITY DISTRICT No violations on file — pop. 1,175
COLUSA INDUSTRIAL PROPERTIES No violations on file — pop. 533
MENF-FOUTS SPRINGS CG No violations on file — pop. 531
COLUSA CO. WWD #1 - GRIMES Older violation on record — pop. 512
MORNING STAR PKG. CO.-WMS. No violations on file — pop. 390
COLUSA CO. WWD #2 - PRINCETON No violations on file — pop. 382
COLUSA CO. SERVICE AREA #2-STONYFORD No violations on file — pop. 250
COLUSA CO. SERVICE AREA #1-CENTURY RANCH No violations on file — pop. 246

NORTHERN TRUCK INC. No violations on file — pop. 200
DEL ORO WC - ARBUCKLE DISTRICT No violations on file — pop. 185
DEL ORO WATER CO.-WALNUT RANCH No violations on file — pop. 182
COLUSA LANDING No violations on file — pop. 168
SUN VALLEY RICE COMPANY No violations on file — pop. 151
COLUSA MOBILE TRAILER PARK No violations on file — pop. 140
CRUISE N TARRY No violations on file — pop. 135
ARBUCKLE GOLF CLUB No violations on file — pop. 126
OLAM SPICES AND VEGETABLE INGREDIENTS No violations on file — pop. 120
MENF-LETTS LAKE CG No violations on file — pop. 118
WILLOW CREEK M.W.C.-CLARKVILLE No violations on file — pop. 110
WILBUR HOT SPRINGS No violations on file — pop. 97
ADAM'S VEGETABLE OILS No violations on file — pop. 95
ADM RICE INC. No violations on file — pop. 87
FOUTS SPRINGS YOUTH FACILITY No violations on file — pop. 70
RICHMOND HUNTING CLUB - ARBUCKLE No violations on file — pop. 63
HIGHWAY 20 TRAILER PARK No violations on file — pop. 63
BUTTE LODGE DUCK CLUB No violations on file — pop. 60
ARBUCKLE RICHMOND HUNTING CLUB No violations on file — pop. 53
COPA CABANA No violations on file — pop. 50
BRADLEY'S WATER SUPPLY No violations on file — pop. 50
TERHEL FARMS TRAILER PARK #2 No violations on file — pop. 50
LA ESCONDIDA No violations on file — pop. 50
WADHAM ENERGY No violations on file — pop. 50
AMERICAN RICE, INC. No violations on file — pop. 50
GRIMES BOAT LANDING No violations on file — pop. 50
NORTHERN CALIFORNIA DUCK CLUB No violations on file — pop. 40
LODOGA INN No violations on file — pop. 40
RICHMOND HUNTING CLUB-MAXWELL No violations on file — pop. 40
DE VOR NURSERIES No violations on file — pop. 35
WILLOW CREEK M.W.C.-LAMBERTVILLE No violations on file — pop. 31
CINTI & SCHRAMM DUCK CLUB No violations on file — pop. 30
PORTER INDEPENDENT ENTERPRISES No violations on file — pop. 30
TERHEL FARMS TRAILER PARK 01 No violations on file — pop. 26
KINGDOM HALL OF JEHOVAH'S WITNESS-WMS No violations on file — pop. 26
TERHEL FARMS TRAILER PARK 02 No violations on file — pop. 26 — serves COLUSA
RON BARNES No violations on file — pop. 25
TERNEL FARMS INC No violations on file — pop. 25
WHITE MALLARD DUCK CLUB No violations on file — pop. 25
HALSEY WATER SUPPLY No violations on file — pop. 25
COLUSA AIRPORT No violations on file — pop. 25
FOUR CORNERS STATION No violations on file — pop. 25
MIRAMONTES CAMP No violations on file — pop. 25
SQUAW CREEK WATER SYSTEM No violations on file — pop. 25
MAYBERRY WATER SYSTEM No violations on file — pop. 25
T&P FARMS No violations on file — pop. 25
WARD'S BOAT LANDING No violations on file — pop. 25
RIVER VISTA FARMS No violations on file — pop. 25
COLUSA TRACTOR COMPANY No violations on file — pop. 22
ZUMALT I G REESE ORCHARD No violations on file — pop. 15
I G ZUMWALT No violations on file — pop. 15
VANN BROTHERS LABOR CAMP No violations on file — pop. 15
KALFSBEEK LABOR CAMP No violations on file — pop. 10
SUNDOWN DRIVE-IN THEATER No violations on file — pop. 1
VILLA ALMENDRA 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?

Colusa County, CA Water Quality Report

Violations on file

Contaminants found

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Individual water providers