Western Hills Water District/diablo Gran
EPA ID: CA5010039 · 2,000 people served · 3 ZIP codes
ZipCheckup's reading of EPA SDWIS for Western Hills Water District/diablo Gran (CA5010039): no EPA violations recorded in the last five years. Unlike many utilities its size, Western Hills Water District/diablo Gran carries a violation-free five-year record - no EPA notices, no MCL exceedances, serving 2,000 people.
Data: EPA SDWIS
Service Area Map
Coverage area for Western Hills Water District/diablo Gran Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Western Hills Water District/diablo Gran serves a community with a median household income of $58,333 and an estimated 32,265 residents across its service area. Approximately 47% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: 54% of the population in this service area is classified as disadvantaged under EPA's EJScreen criteria. Communities with higher disadvantaged populations often face disproportionate environmental and health burdens, including aging water infrastructure and limited resources for remediation.
🌊 Where Does Your Water Come From?
Western Hills Water District/diablo Gran'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
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
Western Hills Water District/diablo Gran (EPA ID: CA5010039) is a community water system in California that serves approximately 2,000 people from surface water sources.
This system provides water to 3 ZIP codes across 3 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 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 3 (Low Risk)
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.
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Western Hills Water District/diablo Gran (CA5010039) on EPA.gov.
Frequently Asked Questions
Is Western Hills Water District/diablo Gran water safe to drink?
The accepted 2026Q2 ECHO snapshot contains zero violation records for Western Hills Water District/diablo Gran 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 Western Hills Water District/diablo Gran serve?
Western Hills Water District/diablo Gran serves approximately 2,000 people across 3 ZIP codes in California.
Where does Western Hills Water District/diablo Gran get its water?
The primary water source is surface water.
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). Western Hills Water District/diablo Gran Water Report, CA. https://zipcheckup.com/water-system/ca5010039/
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title = {{Western Hills Water District/diablo Gran Water Report, CA}},
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