Walnut Valley Water District
EPA ID: CA1910234 · 100,941 people served · 6 ZIP codes
ZipCheckup's reading of EPA records for Walnut Valley Water District (CA1910234): no drinking-water violations recorded since 2021. Walnut Valley Water District is listed without violations in federal records, across a service area of 100,941 people.
Data: EPA SDWIS
Service Area Map
Coverage area for Walnut Valley Water District Source: EPA SDWIS service area boundaries.
Service area boundary - average Home Safety grade of mapped ZIPs: C
Demographics of ZIP Codes Served
The ZIP codes associated with Walnut Valley Water District have a median household income of $89,919 and about 263,364 residents live in those ZIP codes (Census; not the number of people this system supplies). Approximately 77% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: On average, 49% of census tracts in the counties mapped to this service area are designated disadvantaged by the federal Climate and Economic Justice Screening Tool (CEJST, 2022 version). 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?
Walnut Valley Water District'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 70th 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. 29 detections recorded. 5 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
Walnut Valley Water District (EPA ID: CA1910234) is a community water system in California that serves approximately 100,941 people from surface water sources.
This system provides water to 6 ZIP codes across 5 communities.
ZIP-Area Home Safety Context: C (67/100)
This is the average Home Safety Score for 2 of 6 service-area ZIP codes with all required score domains observed. It is not a grade for the water utility.
Model 4.0.0 uses SDWIS identity plus accepted ECHO SDWA lifecycle-based water compliance, the UCMR 5 PFAS MCL screen, EPA radon zone, and annual EPA AirData AQI across three equally weighted domains. Missing required evidence suppresses the score.
Violation History
Lead & Copper
EPA Lead and Copper Rule evidence attributed directly to this water system:
| Lead Level | Exceeds Action Level | Sample Date |
|---|---|---|
| Below the reporting limit | No | 2024-12-31 |
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
6 of 6 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.
- 91748 - Rowland Heights
- 91765 - Diamond Bar
- 91766 - Pomona
- 91768 - Pomona
- 91789 - Walnut
- 91792 - West Covina
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View available EPA compliance records for Walnut Valley Water District (CA1910234) on EPA.gov.
Frequently Asked Questions
Is Walnut Valley Water District water safe to drink?
The accepted 2026Q2 ECHO snapshot contains zero violation records for Walnut Valley Water District 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 Walnut Valley Water District serve?
Walnut Valley Water District serves approximately 100,941 people across 6 ZIP codes in California.
Where does Walnut Valley Water District 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.). Walnut Valley Water District, CA: Serves 101K People. https://zipcheckup.com/water-system/ca1910234/
@misc{zipcheckup-water-system-ca1910234,
author = {{ZipCheckup}},
title = {{Walnut Valley Water District, CA: Serves 101K People}},
year = {n.d.},
url = {https://zipcheckup.com/water-system/ca1910234/}
}
What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Walnut Valley Water District (EPA ID: CA1910234) - request the latest Consumer Confidence Report or ask about specific contaminants.