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Tap water quality report

City of Cupertino

EPA monitoring tested this supplier for 78 contaminants and detected 5. A detection doesn't automatically mean the water is unsafe — the level and EPA source for each is below.

78
contaminants tested
5
detected
16,336
people served
15
health-based violations
California rankingsLead in CaliforniaPFAS in California
Water source
SWP
Ownership
Local government
Counties served
Santa Clara

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.

15
health-based violations
15
violations on file
0
still open
ViolationTypeStatusPeriod
MCL Health-based Resolved 1993-02-22 → 1993-03-31
MCL Health-based Resolved 1993-02-22 → 1993-03-31
MCL Health-based Resolved 1993-02-22 → 1993-03-31
MCL Health-based Resolved 1993-02-22 → 1993-03-31
MCL Health-based Resolved 1992-11-24 → 1993-01-22
MCL Health-based Resolved 1992-11-24 → 1993-01-22
MCL Health-based Resolved 1992-11-24 → 1993-01-22
MCL Health-based Resolved 1992-11-24 → 1993-01-22
MCL Health-based Resolved 1992-09-01 → 1992-11-24
MCL Health-based Resolved 1992-09-01 → 1992-11-24

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
4520 µg/L 45%
of the EPA limit 10000 µg/L
 28/28 SYR4 2012–2019
Lead
0.0 mg/L 0%
of the EPA limit 0.0150 mg/L
 7/7 LCR 2022
Barium
120 µg/L 6%
of the EPA limit 2000 µg/L
 6/6 SYR4 2012–2019
Fluoride
210 µg/L 5.3%
of the EPA limit 4000 µg/L
 6/6 SYR4 2012–2019
Nitrate-Nitrite
4500 µg/L 45%
of the EPA limit 10000 µg/L
 4/4 SYR4 2016–2019
73 contaminants tested, none detected
1,1,1-Trichloroethane1,1,2-Trichloroethane1,1-Dichloroethylene1,2,4-Trichlorobenzene1,2-Dichloroethane1,2-Dichloropropane11Cl-PF3OUdS2,4,5-TP2,4-D4:2 Fts6:2 Fts8:2 Fts9Cl-PF3ONSAdonaAntimony, TotalArsenicAsbestosBenzeneBenzo(A)PyreneBeryllium, TotalChlorobenzeneCopperCyanideCadmiumCarbon TetrachlorideChromiumDichloromethaneDalaponDi(2-ethylhexyl) AdipateDi(2-ethylhexyl) PhthalateDinosebEthylbenzeneHfpo-DaLeadMercuryNetfosaaNfdhaNmefosaaNitritePfbaPFBSPfdaPfdoaPfeesaPfhpaPfhpsPfhxaPFHXSPfmbaPfmpaPFNAPFOAPFOSPfpeaPfpesPftaPftrdaPfunaPentachlorophenolPicloramSeleniumStyreneTetrachloroethyleneThallium, TotalTolueneTrichloroethyleneVinyl ChlorideXylenes, Totalcis-1,2-DichloroethyleneLithiumO-DichlorobenzeneP-Dichlorobenzenetrans-1,2-Dichloroethylene

Utility contact

Contact
DELORENZO, SUZANNE
Phone
408-918-7254
Email
suzanne.delorenzo@sjwater.com

Frequently asked questions about City of Cupertino

Is City of Cupertino tap water safe to drink?

EPA monitoring detected 5 contaminants in City of Cupertino'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 Cupertino's water?

EPA monitoring detected Nitrate, Lead, Barium, Fluoride, Nitrate-Nitrite. The full list with the level and data source for each is above.

How many people does City of Cupertino serve?

City of Cupertino reports serving 16,336 people in California, per its EPA record.

Has City of Cupertino had any water quality violations?

The EPA has 15 violations on file for City of Cupertino, of which 15 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.