Drinking water quality · 2024
· Verified
What's in City of Cupertino, CA tap water
20 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
- 20
- Over federal limit
- 0
- Approaching the limit
- 1
- Service area
- CA
Where your water comes from · EPA SDWIS
City of Cupertino, CA's drinking water comes from ground water, drawn from 2 sources.
Source
- FLOWERING PEAR COURT
- FRANCO COURT
Treatment
- MANN STATION CHLORINATION STATION
Distribution
Also buys water from SANTA CLARA VALLEY WATER DISTRICT, SAN JOSE WATER, and 1 more.
Historical readings · EPA Six-Year Review (2012–2019)
4 historically-detected contaminants in City of Cupertino, CA
Every U.S. public water system reports compliance-monitoring data to EPA. The Six-Year Review releases the 2012–2019 window as a single dataset — here's what your system reported, year by year. Values shown are the highest detection per analyte per year, compared to the federal MCL.
| Contaminant | Worst detection | EPA limit | Years (2012–2019) |
|---|---|---|---|
NITRATE worst: 2012 | 4.52 mg/L within | 10 mg/L | '12'13'15'16'17'18'19 |
NITRATE NITRITE worst: 2016 | 4.5 mg/L within | 10 mg/L | '16'19 |
BARIUM worst: 2012 | 0.12 mg/L within near national p90 | 2 mg/L | '12'13'16'19 |
FLUORIDE worst: 2013 | 0.21 mg/L within | 4 mg/L | '12'13'16'19 |
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 | 80 ug/LMCL | Approaching the limit |
| HAA5Haloacetic acids — a group of five disinfection byproducts formed when disinfectants react with organic matter. | 35.8 ug/LAverageSite Average | 60 ug/LMCL | Within the limit |
| BromateA disinfection byproduct formed when bromide-containing water is treated with ozone. | 1.7 ug/LAverageVW Surface Water | 10 ug/LMCL | Within the limit |
+By source (3)— VW Surface Water, Mountain Surface Water, Groundwater
| |||
Metals
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| Chromium, TotalTotal chromium — the sum of all chromium forms, from natural deposits and industrial discharge. | 3.2 ug/LAverageGroundwater | 10 ug/LMCL | Within the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
| CopperA metal that enters water from corroding household plumbing. | 0.23 mg/L90th percentileAt the tap | 1.3 mg/LAction level | Within the limit |
| AluminumA common element sometimes used as a treatment coagulant. | Not detected mg/LAverageVW Surface Water | 1 mg/LMCL | Within the limit |
+By source (3)— Groundwater, Mountain Surface Water, VW Surface Water
| |||
| ArsenicA naturally occurring element that also enters water from industry and agriculture. | Not detected ug/LAverageMountain Surface Water | 10 ug/LMCL | 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 | 15 ug/LAction level | None detected |
| SeleniumA trace element from natural deposits and industrial discharge. | Not detected ug/LAverageMountain Surface Water | 50 ug/LMCL | None detected |
+By source (3)— Mountain Surface Water, VW Surface Water, Groundwater
| |||
Disinfectants
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| ChlorineA disinfectant added to drinking water to kill bacteria and viruses. | 1.17 mg/LRunning annual avgSystem-wide | 4 mg/LMRDL | Within the limit |
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
| |||
| UraniumA naturally occurring radioactive metal from erosion of natural deposits. | 1.3 pCi/LAverageVW Surface Water | 20 pCi/LMCL | Within the limit |
+By source (3)— Groundwater, VW Surface Water, Mountain Surface Water
| |||
| Combined RadiumCombined radium-226 and radium-228 — naturally occurring radioactive elements. | Not detected pCi/LAverageGroundwater | 5 pCi/LMCL | Within the limit |
+By source (3)— Groundwater, VW Surface Water, Mountain 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 |
Physical & aggregate
| Contaminant | Measured | Federal limit | Status |
|---|---|---|---|
| TurbidityA measure of cloudiness from suspended particles in the water. | 0.9 NTUAverageGroundwater | None set | Detected — no federal limit |
+By source (3)— Groundwater, VW Surface Water, Mountain Surface Water
| |||
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 20 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?
20 contaminants were measured in City of Cupertino, CA's 2024 Consumer Confidence Report, spanning metals, disinfection byproducts, and microbial. 17 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?
One contaminant is between 80% and 100% of the federal limit in this report: TTHM. 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.