Lead Pipe Map

California · population 1,428

Lead pipes in Colma, CA

15,446 lines still unidentified

Most of Colma (population 1,428) gets its water from California Water Service-S San Francisco. It reported no confirmed lead service lines, but 15,446 of 17,175 lines are still listed as unknown material, so lead hasn't been ruled out.

0% of California Water Service-S San Francisco's service lines are lead or galvanized requiring replacement, lower than the California average (0.1%) and lower than the national average (3.1%).

0Lead
0Galvanized, replace
15,446Unknown material
1,729Non-lead

Latest lead test for California Water Service-S San Francisco (Jan 2023–Dec 2025): 4.1 ppb at the 90th percentile, against a 15 ppb federal action level. Full test history.

Compliance record: EPA lists no Lead and Copper Rule violations since 2015 for California Water Service-S San Francisco.

Water systems serving Colma

Water systemLeadGalv.Unknown% lead
California Water Service-S San FranciscoMain system0015,4460%
City of Daly CityServes nearby areas0000%

Matched from EPA water system service area boundaries and the cities each system reports serving. Edges of the city may be served by a neighboring system; your water bill names your utility.

Check your address in Colma

The counts above cover the whole water system. To see whether your line is lead, look up your address on California Water Service-S San Francisco's official inventory. Utilities had to make these public by October 16, 2024.

Find the official inventory mapCalifornia Water Service-S San Francisco details

No map yet? Do the 2-minute scratch and magnet test.

Protect your drinking water

If your line is lead, galvanized or unknown, use a filter certified to NSF/ANSI 53 for lead for drinking, cooking and baby formula, and use only cold water.

Pitcher filtersCheapest start. Pick one certified to NSF/ANSI 53 for lead, such as Brita Elite, PUR Plus or ZeroWater.See pitchers Faucet-mount filtersFilters straight from the tap. Look for NSF/ANSI 53 lead reduction on the box.See faucet filters Under-sink systemsBest for families. Carbon block (NSF 53) or reverse osmosis (NSF 58) units rated for lead.See under-sink

Choosing a lead-certified filter · Testing your water · Replacement cost

Nearby cities

Check another water system

Questions

Does Colma, CA have lead pipes?

None are confirmed, but California Water Service-S San Francisco still lists 15,446 service lines as unknown material.

Who supplies water to Colma?

EPA's service area maps place most of Colma in California Water Service-S San Francisco's service area (PWSID CA4110009). City of Daly City also serves parts of the city or nearby areas.

How do I check whether my Colma home has a lead service line?

Search your address on California Water Service-S San Francisco's service line inventory map. You can also scratch the pipe where water enters your home: lead is soft, dull gray, scratches to shiny silver and doesn't attract a magnet.

When will lead pipes in Colma be replaced?

EPA's Lead and Copper Rule Improvements require most systems to replace lead and galvanized-requiring-replacement lines by December 31, 2037. Ask California Water Service-S San Francisco whether your street is scheduled and whether it covers the private side.