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Tap water quality report

Sonoma, City of

EPA monitoring tested this supplier for 107 contaminants and detected 19. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

107
contaminants tested
19
detected
11,725
people served
2
health-based violations
California rankingsLead in CaliforniaPFAS in California
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.

2
health-based violations
17
violations on file
1
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 2010-01-01 → 2010-01-31
MCL Health-based Resolved 2010-01-01 → 2010-01-31
RPT Monitoring Unaddressed 2025-07-02
MR Monitoring Resolved 2021-04-01 → 2021-06-30
MR Monitoring Resolved 2021-04-01 → 2021-06-30
MR Monitoring Resolved 2020-01-01 → 2020-12-31
MR Monitoring Resolved 2020-01-01 → 2020-12-31
MR Monitoring Resolved 2020-01-01 → 2020-12-31
MR Monitoring Resolved 2020-01-01 → 2020-12-31
MON Monitoring Resolved 2017-11-01 → 2017-11-30

PFAS detected

PFAS are industrial “forever chemicals”. These are the EPA's latest nationwide test results (2023–2025).
ContaminantMaxDetection ratePeriod
Pfhxa 0.0061 µg/L 2/12 2024
PFOA 0.0062 µg/L 2/12 2024

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.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Nitrate
2400 µg/L 24%
of the EPA limit 10000 µg/L
 90/112 SYR4 2012–2019
Arsenic
8.6 µg/L 86%
of the EPA limit 10 µg/L
 61/61 SYR4 2012–2019
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 32/32 LCR 2023
Bromodichloromethane
10 µg/L
No EPA limit set
 30/30 SYR4 2012–2019
Chloroform
19 µg/L
No EPA limit set
 30/30 SYR4 2012–2019
Dibromochloromethane
9.5 µg/L
No EPA limit set
 30/30 SYR4 2012–2019
TTHM
41 µg/L 51%
of the EPA limit 80 µg/L
 30/30 SYR4 2012–2019
Dichloroacetic Acid
5.1 µg/L
No EPA limit set
 27/30 SYR4 2012–2019
Total Haloacetic Acids (HAA5)
9.2 µg/L 15%
of the EPA limit 60 µg/L
 27/30 SYR4 2012–2019
Trichloroacetic Acid
2.4 µg/L
No EPA limit set
 24/30 SYR4 2012–2019
Bromoform
2.3 µg/L
No EPA limit set
 19/30 SYR4 2012–2019
Dibromoacetic Acid
1.9 µg/L
No EPA limit set
 13/30 SYR4 2012–2019
Lithium
40 µg/L
No EPA limit set
 10/12 UCMR-5 2024
Fluoride
460 µg/L 12%
of the EPA limit 4000 µg/L
 9/9 SYR4 2013–2019
Barium
27 µg/L 1.4%
of the EPA limit 2000 µg/L
 2/9 SYR4 2012–2019
Chromium
0.9800 µg/L 1%
of the EPA limit 100 µg/L
 2/9 SYR4 2012–2019
Lead
0.2900 µg/L 1.9%
of the EPA limit 15 µg/L
 1/4 SYR4 2012–2016
88 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCopperCadmiumCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonobromoacetic AcidMonochloroacetic AcidNetfosaaNfdhaNmefosaaNitriteOxamylPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPFHXSPfmbaPfmpaPFNAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
BERGER, MIKE
Phone
707-933-2230
Email
mberger@sonomacity.org

Frequently asked questions about Sonoma, City of

Is Sonoma, City of tap water safe to drink?

EPA monitoring detected 19 contaminants in Sonoma, City of'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, City of's water?

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

How many people does Sonoma, City of serve?

Sonoma, City of reports serving 11,725 people in California, per its EPA record.

Has Sonoma, City of had any water quality violations?

The EPA has 17 violations on file for Sonoma, City of, of which 2 are health-based (a contaminant limit or required treatment was breached) and 1 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.