Rainbow Municipal Water District
EPA ID: CA3710016 · 23,536 people served · 11 ZIP codes
Rainbow Municipal Water District carries zero EPA violations in five years — a spotless record for a utility serving 23,536 residents.
Data: EPA SDWIS Last verified: 2026-04-02
Compliance Trajectory
Stable · Risk tier: High · 95% chance of violation in next 12 months
Violations went from 6 (2021) to 12 (2025). Violation counts have remained relatively steady.
Service Area Map
Coverage area for Rainbow Municipal Water District Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Rainbow Municipal Water District serves a community with a median household income of $99,878 and an estimated 352,130 residents across its service area. Approximately 51% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Rainbow Municipal 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.
About 1% of homes in San Diego 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. 18 detections recorded. 5 exceed federal EPA limits (4 ppt for PFOA/PFOS). 5 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
Rainbow Municipal Water District (EPA ID: CA3710016) is a community water system in California that serves approximately 23,536 people from surface water sources.
This system provides water to 11 ZIP codes across 10 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: 10 ZIP codes confirmed via EPA Community Water System Service Area Boundaries v3 plus 1 additional ZIP inferred from SDWIS registry data. The EPA-confirmed set is the most reliable; SDWIS-inferred entries may be narrower than the real deployment area.
- 92003 — Bonsall
- 92026 — Escondido
- 92028 — Fallbrook
- 92057 — Oceanside
- 92059 — Pala
- 92061 — Pauma Valley
- 92069 — San Marcos
- 92082 — Valley Center
- 92084 — Vista
- 92088 — Fallbrook
- 92562 — Murrieta
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Rainbow Municipal Water District (CA3710016) on EPA.gov.
Frequently Asked Questions
Is Rainbow Municipal Water District water safe to drink?
Based on EPA records, Rainbow Municipal Water District has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Rainbow Municipal Water District serve?
Rainbow Municipal Water District serves approximately 23,536 people across 11 ZIP codes in California.
Where does Rainbow Municipal Water District get its water?
The primary water source is surface water.
Federal UCMR5 PFAS Monitoring: Tested Clean
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were detected.
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:
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.