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Tap water quality report

Zone 7 Water Agency

EPA monitoring tested this supplier for 76 contaminants and detected 14. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

76
contaminants tested
14
detected
40
people served
0
health-based violations
California rankingsLead in CaliforniaPFAS in California
Water source
Surface water
Ownership
Local government
Counties served
Alameda

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.

0
health-based violations
4
violations on file
0
still open
ViolationTypeStatusPeriod
MR Monitoring Resolved 1995-06-01 → 1995-06-30
MR Monitoring Resolved 1995-06-01 → 1995-06-30
MR Monitoring Resolved 1995-06-01 → 1995-06-30
MR Monitoring Resolved 1995-06-01 → 1995-06-30

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.
ContaminantLevel vs EPA limitDetection rateSourcePeriod
Nitrate
4700.8 µg/L 47%
of the EPA limit 10000 µg/L
worst single sample: 11526 µg/L
730/1166 SYR4 2012–2019
Fluoride
100 µg/L 2.5%
of the EPA limit 4000 µg/L
worst single sample: 200 µg/L
401/587 SYR4 2012–2019
Combined Uranium
5.0847 µg/L 17%
of the EPA limit 30 µg/L
worst single sample: 6.258 µg/L
210/509 SYR4 2012–2019
Barium
320 µg/L 16%
of the EPA limit 2000 µg/L
worst single sample: 390 µg/L
206/519 SYR4 2012–2019
Arsenic
5.54 µg/L 55%
of the EPA limit 10 µg/L
worst single sample: 6 µg/L
113/519 SYR4 2012–2019
Selenium
13 µg/L 26%
of the EPA limit 50 µg/L
worst single sample: 14 µg/L
62/512 SYR4 2012–2019
Bromodichloromethane
19.905 µg/L
No EPA limit set
worst single sample: 22.5 µg/L
40/80 SYR4 2012–2019
Chloroform
15.325 µg/L
No EPA limit set
worst single sample: 22.6 µg/L
40/80 SYR4 2012–2019
Dibromochloromethane
23.96 µg/L
No EPA limit set
worst single sample: 32.9 µg/L
40/80 SYR4 2012–2019
Chromium
20 µg/L 20%
of the EPA limit 100 µg/L
worst single sample: 65 µg/L
39/559 SYR4 2012–2019
TTHM
60.94 µg/L 76%
of the EPA limit 80 µg/L
worst single sample: 78.2 µg/L
34/68 SYR4 2012–2018
Bromoform
17.085 µg/L
No EPA limit set
worst single sample: 25.1 µg/L
32/80 SYR4 2012–2019
Lead
0.0067 mg/L 45%
of the EPA limit 0.0150 mg/L
 16/16 LCR 2021
Nitrate-Nitrite
190000 µg/L 1900%
of the EPA limit, at the 95th percentile of samples — 10000 µg/L
 1/2 SYR4 2012–2015
62 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-DIBROMO-3-CHLOROPROPANE1,2-Dichloroethane1,2-Dichloropropane2,3,7,8-TCDD2,4,5-TP2,4-DAntimony, TotalAsbestosAtrazineBhc-GammaBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCopperCyanideCadmiumCarbofuranCarbon TetrachlorideChlordaneDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebDiquatEthylene DibromideEndothallEndrinEthylbenzeneGlyphosateGross Beta Particle ActivityHexachlorobenzeneHeptachlorHeptachlor EpoxideHexachlorocyclopentadieneLassoLeadMercuryMethoxychlorNitriteOxamylPentachlorophenolPicloramSimazineStyreneTetrachloroethyleneThallium, TotalTolueneTotal Polychlorinated Biphenyls (PCB)ToxapheneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
PRYOR, VALERIE
Phone
925-454-5016
Email
[email protected]

Frequently asked questions about Zone 7 Water Agency

Is Zone 7 Water Agency tap water safe to drink?

EPA monitoring detected 14 contaminants in Zone 7 Water Agency'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 Zone 7 Water Agency's water?

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

How many people does Zone 7 Water Agency serve?

Zone 7 Water Agency reports serving 40 people in California, per its EPA record.

Has Zone 7 Water Agency had any water quality violations?

The EPA has 4 violations on file for Zone 7 Water Agency, of which 0 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.