Western Mwd
EPA ID: CA3310049 · 86,062 people served · 26 ZIP codes
Although compliance varies widely among water utilities nationally, Western Mwd stands out with zero EPA violations over five consecutive monitoring years, delivering safe tap water to 86,062 residents and showing no enforcement activity across the entire reporting span.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Worsening · Risk tier: High · 88% chance of violation in next 12 months
Violations went from 3 (2024) to 1 (2025). The pattern suggests growing compliance challenges.
Service Area Map
Coverage area for Western Mwd Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Western Mwd serves a community with a median household income of $91,523 and an estimated 861,554 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: 44% 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 Mwd'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.
About 1% of homes in Riverside County, California rely on private wells rather than public water systems. Private well owners are responsible for their own water testing and treatment.
Infrastructure Risk
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 94 detections recorded. 5 exceed federal EPA limits (4 ppt for PFOA/PFOS). 4 exceed state limits.
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 Mwd (EPA ID: CA3310049) is a community water system in California that serves approximately 86,062 people from surface water sources.
This system provides water to 26 ZIP codes across 7 communities.
Violation History
Lead & Copper
No Lead and Copper Rule sampling data available for this water system.
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: 14 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 12 additional ZIPs inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
- 92501 — Riverside
- 92502 — Riverside
- 92503 — Riverside
- 92504 — Riverside
- 92505 — Riverside
- 92506 — Riverside
- 92507 — Riverside
- 92508 — Riverside
- 92509 — Riverside
- 92513 — Riverside
- 92514 — Riverside
- 92515 — Riverside
- 92516 — Riverside
- 92517 — Riverside
- 92518 — March Air Reserve Base
- 92519 — Riverside
- 92521 — Riverside
- 92522 — Riverside
- 92532 — Lake Elsinore
- 92553 — Moreno Valley
- 92570 — Perris
- 92571 — Perris
- 92592 — Temecula
- 92879 — Corona
- 92881 — Corona
- 92883 — Corona
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Western Mwd (CA3310049) on EPA.gov.
Frequently Asked Questions
Is Western Mwd water safe to drink?
Based on EPA records, Western Mwd has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Western Mwd serve?
Western Mwd serves approximately 86,062 people across 26 ZIP codes in California.
Where does Western Mwd 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 →
Lead Service Line Inventory
Service line breakdown reported under the federal Lead and Copper Rule Improvements (LCRI) inventory requirement:
This system reports zero confirmed lead service lines in its inventory. Unknown-material counts may still warrant verification.
Federal LCRI rule (effective October 2024) requires every public water system to inventory its service lines and complete lead-line replacement within 10 years.
Source: EPA SDWIS Federal Service Line Inventory (Phase 2) · Submitted 2026
ZipCheckup is not affiliated with the utility or state agency. Inventory figures render verbatim from the public LCRI submission cited above; ZipCheckup does not perform inspections or replacements.