Is San Jose, CA tap water safe?

Data: U.S. EPA · How we read the data · How we check it

No federal limits exceeded in EPA data for San Jose Water. 2 PFAS were detected below the limits.

6 public water systems serve parts of San Jose. The largest, San Jose Water, serves 1 million people. Your water bill names your system.

Largest system

San Jose Water

1 million people · Surface water · EPA ID CA4310011

Buys treated water from Santa Clara Valley Water District, City of Cupertino.

PFAS	Highest average	Limit	Status
PFOA Not detected	–	4 ppt	Not detected
PFOS One sample above limit	3.1 ppt	4 ppt	One sample above limit
PFHxS Detected, below limit	4.3 ppt	10 ppt	Detected, below limit
PFNA Not detected	–	10 ppt	Not detected
HFPO-DA (GenX) Not detected	–	10 ppt	Not detected

ppt = parts per trillion. "Highest average" is the highest average at any of the system's entry points, the way EPA compares results with the limits.

Lead: 0 ppb at the 90th percentile (Dec 2025, and 9 in 10 homes sampled were at or below it) Below action level
Health-based violations since 2016: 1

Full San Jose Water results

Across California, 129 of 691 water systems EPA tested had PFAS above a 2024 federal limit, and 26 systems were above the lead action level in results from the last five years. California results.

San Jose homes and lead pipes

60%

of homes built before 1980 (California 56%, US 50%)

built before 1950 (California 14%)

44%

of households rent (California 44%)

Lead service lines and lead solder were allowed until 1986, so homes from before then are the ones to check. San Jose Water's service line inventory lists 0 lead lines and 0 galvanized lines that need replacing (as of 2026-03). Look up your address. Renting? Ask your landlord what the service line is made of, because it's their pipe to replace. How to check your own line.

Housing: Census American Community Survey 2020–2024 5-year estimates for San Jose city (tables B25034, B25003). Estimates for small places have a margin of error.

Which system serves your ZIP code

Based on the ZIP codes each system reported serving. Boundaries don't follow ZIP lines exactly, so your water bill is the final word.

System	ZIP codes in San Jose
San Jose Water 1 million people	95002, 95013, 95110, 95111, 95112, 95113, 95116, 95117, 95118, 95119, 95120, 95121, 95122, 95123, 95124, 95125, 95126, 95127, 95128, 95129, 95130, 95131, 95132, 95133, 95134, 95136, 95138, 95148
Great Oaks Water Company Inc 112,582 people	95139

Other water systems serving San Jose

Great Oaks Water Company Inc
112,582 people · Groundwater · California · reported ZIPs here
PFOS detectedAlso: PFHxS detected · Lithium above screening level
City of San Jose – Evergreen/Edenvale/Coyote
99,783 people · Purchased surface water · California · lists this city
No PFAS above limits
City of San Jose – North San Jose/Alviso
48,082 people · Purchased surface water · California · lists this city
No PFAS above limits
California Water Service King City
14,046 people · Groundwater · California · lists this city
Lithium above screening level
Coast Springs – Cal. Water Service (PUC)
445 people · Surface water · California · reported ZIPs here
Not in EPA's PFAS sample

How nearby cities compare

City	Main water system	PFAS	Lead (90th pct.)
Los Gatos 9 mi San Jose Water	San Jose Water	None above limits	0 ppb
Santa Clara 10 mi City of Santa Clara	City of Santa Clara	None above limits	2.7 ppb
Milpitas 10 mi City of Milpitas	City of Milpitas	None above limits	2.5 ppb
Cupertino 13 mi California Water Service Los Altos Suburban	California Water Service Los Altos Suburban	None above limits	1.5 ppb
Sunnyvale 13 mi City of Sunnyvale	City of Sunnyvale	None above limits	0 ppb
Morgan Hill 15 mi City of Morgan Hill	City of Morgan Hill	None above limits	0 ppb

Questions

Is San Jose tap water safe to drink?

San Jose Water had 1 health-based violation since 2016. Utility data can't show lead from your own pipes: if your home was built before 1986, test your tap. Your utility's annual Consumer Confidence Report is the official summary.

Who supplies water in San Jose, CA?

6 public water systems serve parts of San Jose. The largest is San Jose Water (1 million people). Your water bill names your system. The EPA ID is also on your utility's Consumer Confidence Report.

Does San Jose tap water have PFAS?

San Jose Water had 2 PFAS detected at least once in EPA's 2023–2025 testing, all with averages below the federal limits.

Do San Jose homes have lead pipes?

Census estimates put 60% of San Jose homes as built before 1980 (California: 56%). Lead service lines and lead solder were allowed until 1986, so older homes are more likely to have them. San Jose Water's service line inventory lists 0 lead lines. The only way to know for your home is to check the line where it enters the house and test your tap.

Source: U.S. EPA drinking water records and PFAS testing (UCMR 5). How we read the data.