Is Sonoma Mountain County Water District Tap Water Safe? Quality Report

Water source: Ground water
Ownership: Local government
Counties served: Sonoma

Compliance record

Formal violations the EPA has on file for this supplier. A health-based violation means a contaminant limit or a required treatment was breached; the rest are monitoring or reporting failures — still violations, but not a measured health risk.

health-based violations

violations on file

still open

Violation	Type	Status	Period
MCL	Health-based	Resolved	2011-01-01 → 2011-01-31
MCL	Health-based	Resolved	2011-01-01 → 2011-01-31
MON	Monitoring	Archived	2021-09-01 → 2021-09-30
MR	Monitoring	Resolved	2015-09-01 → 2015-09-30
MR	Monitoring	Resolved	2015-09-01 → 2015-09-30
MR	Monitoring	Resolved	2009-03-01 → 2009-03-31
MR	Monitoring	Resolved	2009-03-01 → 2009-03-31
MR	Monitoring	Resolved	2006-01-01 → 2006-12-31
MR	Monitoring	Resolved	2006-01-01 → 2006-12-31
MR	Monitoring	Resolved	1996-07-01 → 1996-07-31

Other contaminants detected

Each bar shows the measured level as a share of the EPA limit: green is well under, amber is close to it, red is over. For lead and copper the limit applies to exactly the 90th-percentile figure shown, so red there means a real exceedance. For everything else the limit applies to a running annual average while the figure is the single worst sample on record — over 100% is worth reading, but is not by itself a violation. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
Lead	0.0080 mg/L 53% of the EPA limit 0.0150 mg/L	25/25	LCR	2025
Fluoride	340 µg/L 8.5% of the EPA limit 4000 µg/L	5/5	SYR4	2013–2019
Bromodichloromethane	6.1 µg/L No EPA limit set	3/4	SYR4	2012–2019
Chloroform	8.2 µg/L No EPA limit set	3/4	SYR4	2012–2019
TTHM	17 µg/L 21% of the EPA limit 80 µg/L	3/4	SYR4	2012–2019
Dibromochloromethane	3 µg/L No EPA limit set	2/4	SYR4	2012–2019
Barium	430 µg/L 22% of the EPA limit 2000 µg/L	1/5	SYR4	2013–2019
Toluene	0.6500 µg/L 0.1% of the EPA limit 1000 µg/L	1/6	SYR4	2012–2014

63 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane2,4,5-TP2,4-DAntimony, TotalArsenicAsbestosAtrazineBhc-GammaBenzeneBeryllium, TotalBromoformChlorobenzeneCopperCadmiumCarbofuranCarbon TetrachlorideChlordaneChromiumDichloromethaneDalaponDibromoacetic AcidDichloroacetic AcidDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonobromoacetic AcidMonochloroacetic AcidNitrateNitriteOxamylPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTotal Haloacetic Acids (HAA5)Total Polychlorinated Biphenyls (PCB)ToxapheneTrichloroacetic AcidTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact: ADAMS, KRISTINE
Phone: 707-328-5814
Email: abgaboobooks@gmail.com

Frequently asked questions about Sonoma Mountain County Water District

Is Sonoma Mountain County Water District tap water safe to drink?

EPA monitoring detected 8 contaminants in Sonoma Mountain County Water District's water. A detection isn't the same as a violation — most levels are within federal limits. See each level and source above, and the utility's annual Consumer Confidence Report for its official compliance status.

What contaminants were detected in Sonoma Mountain County Water District's water?

EPA monitoring detected Lead, Fluoride, Bromodichloromethane, Chloroform, TTHM, and others. The full list with the level and data source for each is above.

How many people does Sonoma Mountain County Water District serve?

Sonoma Mountain County Water District reports serving 181 people in California, per its EPA record.

Has Sonoma Mountain County Water District had any water quality violations?

The EPA has 19 violations on file for Sonoma Mountain County Water District, of which 2 are health-based (a contaminant limit or required treatment was breached) and 0 remain open. The rest are monitoring or reporting failures.

Where does this data come from?

Every figure is official EPA drinking-water monitoring — the Lead & Copper Rule, the UCMR-5 nationwide testing program, and the EPA Six-Year Review — not our own testing. Each number is labelled with its source and period.