Tap Water Results

Is Palo Alto, CA tap water safe?

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

Summary

No federal limits exceeded in EPA data for City of Palo Alto.

2 public water systems serve parts of Palo Alto. The largest, City of Palo Alto, serves 67,658 people. Your water bill names your system.

Largest system

City of Palo Alto

67,658 people · Purchased surface water · EPA ID CA4310009

Buys treated water from San Francisco Regional Water System, Stanford University Water System, City of East Palo Alto, Purissima Hills Water District, City of Mountain View.

PFASHighest averageLimitStatus
PFOA
Not detected
–4 pptNot detected
PFOS
Not detected
–4 pptNot detected
PFHxS
Not detected
–10 pptNot detected
PFNA
Not detected
–10 pptNot detected
HFPO-DA (GenX)
Not detected
–10 pptNot 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 2023, and 9 in 10 homes sampled were at or below it) Below action level
Health-based violations since 2016: 0

Full City of Palo Alto 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.

Palo Alto homes and lead pipes

70%
of homes built before 1980 (California 56%, US 50%)
22%
built before 1950 (California 14%)
45%
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. 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 Palo Alto city (tables B25034, B25003). Estimates for small places have a margin of error.

Other water systems serving Palo Alto

How nearby cities compare

CityMain water systemPFASLead (90th pct.)
Los Altos 3 mi
California Water Service Los Altos Suburban
California Water Service Los Altos SuburbanNone above limits1.5 ppb
Mountain View 4 mi
City of Mountain View
City of Mountain ViewNone above limits0 ppb
East Palo Alto 5 mi
City of East Palo Alto
City of East Palo AltoNone above limits0 ppb
Menlo Park 6 mi
California Water Service – Bear Gulch
California Water Service – Bear GulchNone above limits4 ppb
Sunnyvale 6 mi
City of Sunnyvale
City of SunnyvaleNone above limits0 ppb
Cupertino 8 mi
California Water Service Los Altos Suburban
California Water Service Los Altos SuburbanNone above limits1.5 ppb
Palo Alto ZIP codes (5)
  • 94022
  • 94301
  • 94303
  • 94304
  • 94306

Questions

Is Palo Alto tap water safe to drink?

City of Palo Alto has had no health-based violations 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 Palo Alto, CA?

2 public water systems serve parts of Palo Alto. The largest is City of Palo Alto (67,658 people). Your water bill names your system. The EPA ID is also on your utility's Consumer Confidence Report.

Does Palo Alto tap water have PFAS?

None detected above EPA's reporting limits. City of Palo Alto had no PFAS detected in EPA's 2023–2025 testing. "Not detected" means below the reporting limit (about 2 to 20 ppt), not proven zero.

Do Palo Alto homes have lead pipes?

Census estimates put 70% of Palo Alto 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. City of Palo Alto's service line inventory says what your line is made of. 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.