California Water Service-s San Francisco
EPA ID: CA4110009 · 64,146 people served · 5 ZIP codes
ZipCheckup's reading of EPA records for California Water Service-s San Francisco (CA4110009): no drinking-water violations recorded since 2021. No violations appear in the federal EPA file for California Water Service-s San Francisco, which supplies 64,146 people.
Data: EPA SDWIS
Service Area Map
Coverage area for California Water Service-s San Francisco Source: EPA SDWIS service area boundaries.
Service area boundary
Demographics of ZIP Codes Served
The ZIP codes associated with California Water Service-s San Francisco have a median household income of $129,759 and about 180,144 residents live in those ZIP codes (Census; not the number of people this system supplies). Approximately 78% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
California Water Service-s San Francisco's water is drawn from rivers, lakes, or reservoirs. Surface water sources are more exposed to agricultural runoff, stormwater, and upstream discharges, but they typically receive more intensive treatment before reaching your tap.
Superfund Proximity Note: This service area ranks in the 60th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
PFAS in ZIP Codes This System Serves
PFAS ("forever chemicals") have been reported in samples from water systems associated with the ZIP codes in this system's area. These results can come from other water systems serving the same ZIP codes; check the UCMR5 section for any results reported for this system. 6 detections recorded. 2 detections are above the level of a federal PFAS MCL (4 ppt for PFOA and PFOS), with compliance required from 2029.
Comparable Water Systems
Similar-sized systems in California
Estimated Remediation Costs
Average estimated costs across ZIP codes served by this system
Based on national averages for common remediation projects. Actual costs vary by property. Only issues flagged by EPA, FEMA, or state data for each ZIP code are included.
System Overview
California Water Service-s San Francisco (EPA ID: CA4110009) is a community water system in California that serves approximately 64,146 people from surface water sources.
This system provides water to 5 ZIP codes across 4 communities.
Violation History
Lead & Copper
EPA Lead and Copper Rule evidence attributed directly to this water system:
| Lead Level | Exceeds Action Level | Sample Date |
|---|---|---|
| 0.0041 mg/L | No | 2025-12-31 |
No copper action-level exceedance record appears for this PWSID in the accepted LCR snapshot. This does not establish a clean copper measurement.
Radon Risk in Service Area
5 of 5 ZIP records with known zones are in EPA Radon Zone 2.
The EPA recommends testing all homes regardless of radon zone. County radon zones cannot replace an in-home radon test.
ZIP Codes Served
Coverage: Service area ZIP codes sourced from EPA Community Water System Service Area Boundaries v3 (March 2026 release). These ZIPs reflect the actual deployment footprint recorded by CA or modeled from parcel and building-footprint data.
- 94005 - Brisbane
- 94014 - Daly City
- 94015 - Daly City
- 94080 - South San Francisco
- 94128 - San Francisco
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View available EPA compliance records for California Water Service-s San Francisco (CA4110009) on EPA.gov.
Frequently Asked Questions
Is California Water Service-s San Francisco water safe to drink?
The accepted 2026Q2 ECHO snapshot contains zero violation records for California Water Service-s San Francisco in the inclusive 2021-2026 record-year window. This is a compliance-record finding, not a guarantee about water at a specific tap.
How many people does California Water Service-s San Francisco serve?
California Water Service-s San Francisco serves approximately 64,146 people across 5 ZIP codes in California.
Where does California Water Service-s San Francisco get its water?
The primary water source is surface water.
Federal UCMR5 PFAS Monitoring: No PFAS Reported Above Reporting Levels
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were reported above UCMR5 minimum reporting levels.
EPA's April 2024 PFAS rule sets MCLs of 4 ppt for PFOA and PFOS and 10 ppt for PFHxS, PFNA and HFPO-DA (GenX); water systems must comply from 2029. Other PFAS compounds have no individual federal MCL. A state standard is shown only where this system's state has its own enforceable PFAS limit. Detection results are EPA UCMR5 samples, not a measurement at your tap.
Source: U.S. EPA UCMR5 (Unregulated Contaminant Monitoring Rule, 5th cycle) — per-system federal sampling, 2023–2025. EPA UCMR5 monitoring program →
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). California Water Service-s San Francisco: Serves 64K People. https://zipcheckup.com/water-system/ca4110009/
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