Cwsc Los Altos Suburban
EPA ID: CA4310001 · 69,973 people served · 10 ZIP codes
ZipCheckup's reading of EPA SDWIS for Cwsc Los Altos Suburban (CA4310001): no EPA violations recorded in the last five years. Cwsc Los Altos Suburban earns a clean bill from EPA monitoring - no violations in five years across a service area of 69,973 people.
Data: EPA SDWIS
Service Area Map
Coverage area for Cwsc Los Altos Suburban Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Cwsc Los Altos Suburban serves a community with a median household income of $186,056 and an estimated 384,193 residents across its service area. Approximately 73% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Cwsc Los Altos Suburban'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 80th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 10 detections recorded. 1 exceeds federal EPA limits (4 ppt for PFOA/PFOS).
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
Cwsc Los Altos Suburban (EPA ID: CA4310001) is a community water system in California that serves approximately 69,973 people from surface water sources.
This system provides water to 10 ZIP codes across 6 communities.
Violation History
Lead & Copper
EPA Lead and Copper Rule evidence attributed directly to this water system:
| Lead Level | Exceeds Action Level | Sample Date |
|---|---|---|
| 0.0015 mg/L | No | N/A |
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
Dominant radon zone for ZIP codes served by this system: Zone 2 (Moderate Risk)
The EPA recommends testing homes in Zone 1 and Zone 2 areas for radon.
Need help with your water quality?
Typical cost: Water test: typically $20–$50 (DIY kit) · Professional inspection: $150–$400
Find the Right Water FilterFree tip: Let cold water run for 2 minutes before drinking — this helps flush lead from your pipes.
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.
- 94022 - Los Altos
- 94024 - Los Altos
- 94040 - Mountain View
- 94041 - Mountain View
- 94043 - Mountain View
- 94086 - Sunnyvale
- 94087 - Sunnyvale
- 94306 - Palo Alto
- 95014 - Cupertino
- 95051 - Santa Clara
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Cwsc Los Altos Suburban (CA4310001) on EPA.gov.
Frequently Asked Questions
Is Cwsc Los Altos Suburban water safe to drink?
The accepted 2026Q2 ECHO snapshot contains zero violation records for Cwsc Los Altos Suburban 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 Cwsc Los Altos Suburban serve?
Cwsc Los Altos Suburban serves approximately 69,973 people across 10 ZIP codes in California.
Where does Cwsc Los Altos Suburban get its water?
The primary water source is surface water.
Federal UCMR5 PFAS Monitoring: Detected
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). PFAS compounds were detected below the current state-enforceable MCL.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
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.). Cwsc Los Altos Suburban, CA: Serves 70K People. https://zipcheckup.com/water-system/ca4310001/
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