Is City of Antioch Tap Water Safe? Quality Report

Water source: Surface water
Ownership: Local government
Counties served: Contra Costa

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
TT	Health-based	Resolved	1997-01-01 → 1997-01-31
TT	Health-based	Resolved	1997-01-01 → 1997-01-31
MCL	Health-based	Resolved	1992-11-01 → 1992-11-30
MCL	Health-based	Resolved	1992-11-01 → 1992-11-30
MCL	Health-based	Resolved	1992-01-01 → 1992-01-31
MCL	Health-based	Resolved	1992-01-01 → 1992-01-31

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 95th percentile of this system's samples — over 100% is worth reading, but is not by itself a violation. Where a single sample came in higher than that percentile, it is noted under the bar. Formal violations are listed separately.

Contaminant	Level vs EPA limit	Detection rate	Source	Period
Nitrate	791 µg/L 7.9% of the EPA limit 10000 µg/L worst single sample: 994.4 µg/L	56/192	SYR4	2012–2019
Fluoride	815 µg/L 20% of the EPA limit 4000 µg/L worst single sample: 950 µg/L	36/64	SYR4	2012–2019
Arsenic	4.48 µg/L 45% of the EPA limit 10 µg/L worst single sample: 4.7 µg/L	33/62	SYR4	2012–2019
Bromodichloromethane	14 µg/L No EPA limit set worst single sample: 24 µg/L	28/28	SYR4	2012–2019
Chloroform	13.65 µg/L No EPA limit set worst single sample: 24 µg/L	28/28	SYR4	2012–2019
TTHM	46.6 µg/L 58% of the EPA limit 80 µg/L worst single sample: 74 µg/L	28/28	SYR4	2012–2019
Dibromochloromethane	15.8 µg/L No EPA limit set worst single sample: 28 µg/L	25/28	SYR4	2012–2019
Bromoform	9.1 µg/L No EPA limit set worst single sample: 12 µg/L	21/28	SYR4	2012–2019
Lead	0.0 mg/L 0% of the EPA limit 0.0150 mg/L	21/21	LCR	2024
Nitrate-Nitrite	646500 µg/L 6465% of the EPA limit, at the 95th percentile of samples — 10000 µg/L worst single sample: 770000 µg/L	20/47	SYR4	2012–2019
Total Haloacetic Acids (HAA5)	8.2 µg/L 14% of the EPA limit 60 µg/L worst single sample: 8.8 µg/L	16/21	SYR4	2012–2017
Dichloroacetic Acid	4.18 µg/L No EPA limit set worst single sample: 4.6 µg/L	15/21	SYR4	2012–2017
Dibromoacetic Acid	4.22 µg/L No EPA limit set worst single sample: 5 µg/L	14/21	SYR4	2012–2017
Bromate	9.05 µg/L 91% of the EPA limit 10 µg/L worst single sample: 10 µg/L	6/61	SYR4	2012–2017
Barium	158 µg/L 7.9% of the EPA limit 2000 µg/L worst single sample: 160 µg/L	5/62	SYR4	2012–2019
Dichloromethane	3.19 µg/L 64% of the EPA limit 5 µg/L worst single sample: 3.4 µg/L	4/46	SYR4	2012–2019
Cyanide	1.1 µg/L 0.6% of the EPA limit 200 µg/L	2/54	SYR4	2012–2019
Copper	320 µg/L 25% of the EPA limit 1300 µg/L	1/63	SYR4	2012–2019
Cadmium	1.6 µg/L 32% of the EPA limit 5 µg/L	1/62	SYR4	2012–2019
Di(2-ethylhexyl) Adipate	0.2100 µg/L 0.1% of the EPA limit 400 µg/L	1/44	SYR4	2012–2019
Di(2-ethylhexyl) Phthalate	0.2800 µg/L 4.7% of the EPA limit 6 µg/L	1/44	SYR4	2012–2019
Lead	2.8 µg/L 19% of the EPA limit 15 µg/L	1/57	SYR4	2012–2019
Monobromoacetic Acid	2.6 µg/L No EPA limit set	1/21	SYR4	2012–2017
Trichloroacetic Acid	4.2 µg/L No EPA limit set	1/21	SYR4	2012–2017

87 contaminants tested, none detected

1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,3,7,8-TCDD2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCarbofuranCarbon TetrachlorideChlordaneChromiumDalaponDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateHexachlorobenzeneHfpo-DaHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoMercuryMethoxychlorMonochloroacetic AcidNetfosaaNfdhaNmefosaaNitriteOxamylPfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact: WOODLAND, BENJAMIN M.
Phone: 916-767-7536
Email: [email protected]

Frequently asked questions about City of Antioch

Is City of Antioch tap water safe to drink?

EPA monitoring detected 24 contaminants in City of Antioch'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 City of Antioch's water?

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

How many people does City of Antioch serve?

City of Antioch reports serving 115,074 people in California, per its EPA record.

Has City of Antioch had any water quality violations?

The EPA has 6 violations on file for City of Antioch, of which 6 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.