Is Redwood City, 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 City of Redwood City.

4 public water systems serve parts of Redwood City. The largest, City of Redwood City, serves 90,043 people. Your water bill names your system.

Largest system

City of Redwood City

90,043 people · Purchased surface water · EPA ID CA4110022

Buys treated water from San Francisco Public Utilities Commission City Distribution Division, California Water Service – San Carlos, San Francisco Regional Water System, Mid-Peninsula Water District.

PFAS	Highest average	Limit	Status
PFOA Not detected	–	4 ppt	Not detected
PFOS Not detected	–	4 ppt	Not detected
PFHxS Not detected	–	10 ppt	Not detected
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 2024, and 9 in 10 homes sampled were at or below it) Below action level
Health-based violations since 2016: 0

Full City of Redwood City 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.

Redwood City homes and lead pipes

64%

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

18%

built before 1950 (California 14%)

51%

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 Redwood City city (tables B25034, B25003). Estimates for small places have a margin of error.

Other water systems serving Redwood City

California Water Service – Bear Gulch
60,382 people · Surface water · California · reported ZIPs here
No PFAS above limits
California Water Service – San Carlos
34,801 people · Purchased surface water · California · reported ZIPs here
No PFAS above limits
Mid-Peninsula Water District
31,059 people · Purchased surface water · California · reported ZIPs here
No PFAS above limits

How nearby cities compare

City	Main water system	PFAS	Lead (90th pct.)
San Carlos 3 mi California Water Service – San Carlos	California Water Service – San Carlos	None above limits	5.8 ppb
Foster City 4 mi California Water Service – San Mateo	California Water Service – San Mateo	None above limits	4.4 ppb
Menlo Park 4 mi California Water Service – Bear Gulch	California Water Service – Bear Gulch	None above limits	4 ppb
Belmont 4 mi California Water Service – San Mateo	California Water Service – San Mateo	None above limits	4.4 ppb
East Palo Alto 6 mi City of East Palo Alto	City of East Palo Alto	None above limits	0 ppb
San Mateo 6 mi California Water Service – San Mateo	California Water Service – San Mateo	None above limits	4.4 ppb

Redwood City ZIP codes (3)

94061
94063
94065

Questions

Is Redwood City tap water safe to drink?

City of Redwood City 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 Redwood City, CA?

4 public water systems serve parts of Redwood City. The largest is City of Redwood City (90,043 people). Your water bill names your system. The EPA ID is also on your utility's Consumer Confidence Report.

Does Redwood City tap water have PFAS?

None detected above EPA's reporting limits. City of Redwood City 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 Redwood City homes have lead pipes?

Census estimates put 64% of Redwood City 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 Redwood City'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.