Drinking water quality · 2024
What's in City of Cupertino, CA tap water
23 contaminants were measured in the City of Cupertino, CA water system's 2024 annual report. Each is shown below against its federal limit.
- Reporting year
- 2024
- Contaminants measured
- 23
- Over federal limit
- 0
- Approaching the limit
- 2
- Service area
- CA
state-level CCR
Approaching the limit (≥ 80%)
Where your water comes from · EPA SDWIS
City of Cupertino, CA's drinking water comes from ground water, drawn from 2 sources.
Source
2ground water
- FLOWERING PEAR COURT
- FRANCO COURT
Treatment
1treatment plant
- MANN STATION CHLORINATION STATION
Distribution
0storage units
Also buys water from SANTA CLARA VALLEY WATER DISTRICT, SAN JOSE WATER, and 1 more.
Source: EPA SDWIS facilities inventory. Methodology.
Compliance history
Federal Safe Drinking Water Act violation & enforcement records (EPA SDWIS). A violation is a regulatory determination by the state or EPA — separate from the measured levels above.
- Maximum contaminant level exceededHealth-based3 violations on record · most recent Feb 1993resolved
Source: EPA SDWIS / ECHO. View the full federal record on EPA ECHO ↗
Disinfection byproducts
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TTHMTotal trihalomethanes — a group of four chemicals (including chloroform) formed when chlorine reacts with natural organic matter. | 76.96 ug/LAverageSite Average | None set | Approaching the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 35.8 ug/LAverageSite Average | None set | Within the limit |
| BromateA disinfection byproduct formed when bromide-containing water is treated with ozone. | 1.7 ug/LAverageVW Surface Water | None set | Within the limit |
+By source (3)— VW Surface Water, Mountain Surface Water, Groundwater
| |||
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.9 NTUAverageGroundwater | None set | Approaching the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
Other
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Nitrate Nitrite | 3.76 mg/LAverageGroundwater | 10 mg/LMCL | Within the limit |
+By source (3)— Groundwater, VW Surface Water, Mountain Surface Water
| |||
| Chlorine Total | 1.17 mg/LRunning annual avgSystem-wide | 4 mg/LMCL | Within the limit |
| Chromium | 3.2 ug/LAverageGroundwater | None set | Within the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
| Dichloroethylene 11 | Not detected ug/LAverageMountain Surface Water | None set | Within the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
| Trichloroethane 111 | Not detected ug/LAverageMountain Surface Water | None set | Within the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
Inorganic chemicals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| NitrateA compound from fertilizer runoff, septic systems, and erosion of natural deposits. | 3 mg/LAverageGroundwater | 10 mg/LMCL | Within the limit |
+By source (3)— Groundwater, VW Surface Water, Mountain Surface Water
| |||
| FluorideA mineral often added to drinking water to help prevent tooth decay. | 0.8 mg/LAverageVW Surface Water | 4 mg/LMCL | Within the limit |
+By source (3)— VW Surface Water, Groundwater, Mountain Surface Water
| |||
Radionuclides
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Gross AlphaGross alpha particle activity — a combined measure of alpha-emitting radioactive substances. | 3.3 pCi/LAverageVW Surface Water | 15 pCi/LMCL | Within the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
| Combined RadiumCombined radium-226 and radium-228 — naturally occurring radioactive elements. | Not detected pCi/LAverageMountain Surface Water | 5 pCi/LMCL | Within the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
| UraniumA naturally occurring radioactive metal from erosion of natural deposits. | 1.3 pCi/LAverageVW Surface Water | 20 pCi/LMCL | Detected — no federal limit |
+By source (3)— Groundwater, VW Surface Water, Mountain Surface Water
| |||
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| CopperA metal that enters water from corroding household plumbing. | 0.23 mg/L90th percentileAt the tap | 1.3 mg/LAction level | Within the limit |
| BariumA metal from erosion of natural deposits and industrial discharge. | 0.18 mg/LAverageGroundwater | 2 mg/LMCL | Within the limit |
+By source (3)— Groundwater, VW Surface Water, Mountain Surface Water
| |||
| ArsenicA naturally occurring element that also enters water from industry and agriculture. | Not detected ug/LAverageMountain Surface Water | None set | Within the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
| LeadA toxic metal that leaches into water from old service lines, solder, and plumbing fixtures. | Not detected ug/L90th percentileAt the tap | None set | None detected |
| SeleniumA trace element from natural deposits and industrial discharge. | Not detected ug/LAverageMountain Surface Water | None set | None detected |
+By source (3)— Mountain Surface Water, Groundwater, VW Surface Water
| |||
| AluminumA common element sometimes used as a treatment coagulant. | Not detected mg/LAverageMountain Surface Water | None set | Detected — no federal limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
Microbial
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Cryptosporidium | Not detectedAverageMountain Surface Water | None set | Detected — no federal limit |
+By source (2)— Mountain Surface Water, VW Surface Water
| |||
| Giardia lamblia | 0.22AverageMountain Surface Water | None set | Detected — no federal limit |
+By source (2)— Mountain Surface Water, VW Surface Water
| |||
| Total ColiformA group of bacteria used as an indicator of overall water-system sanitation. | 0.13 %AverageSystem-wide | 0 %MCLG | Detected — no federal limit |
Source: City of Cupertino, CA's 2024 Consumer Confidence Report — the annual drinking-water report every U.S. utility is required to publish. The numbers on this page are the utility's own. A water-quality report covers an entire service area, not a single address.
People also ask about City of Cupertino, CA's water
+Is City of Cupertino, CA tap water safe to drink in 2024?
Every one of the 23 contaminants measured in City of Cupertino, CA's 2024 Consumer Confidence Report is below its federal limit. "Safe" under the EPA's drinking-water standards is health-based, not aesthetic — but by those standards, no measured contaminant in this report exceeds its enforceable threshold. Individual health concerns (e.g. immunocompromised, infant, pregnancy) may warrant additional filtering regardless of compliance.
+What contaminants are in City of Cupertino, CA tap water?
23 contaminants were measured in City of Cupertino, CA's 2024 Consumer Confidence Report, spanning metals, other, and disinfection byproducts. 10 have an enforceable federal limit; the rest are detected but unregulated. Every measured value, in the utility's own units, is on this page.
+Are any contaminants in City of Cupertino, CA tap water approaching the federal limit?
2 contaminants are between 80% and 100% of the federal limit in this report: TTHM and Turbidity. Approaching means measured but not in violation — a margin that can close quickly if conditions change.
+Where does the data on this page come from?
Every value is transcribed from City of Cupertino, CA's 2024 Consumer Confidence Report — the annual drinking-water report every U.S. public water utility is required by federal law to publish. The original source document is archived and viewable on this site. A water-quality report covers an entire service area, not a single address.
+How often is City of Cupertino, CA's water quality data updated?
Each U.S. public water utility publishes one Consumer Confidence Report per year, covering the prior calendar year's measurements. This page reflects the 2024 report; a new report will replace it once the utility publishes its next annual update.
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