City of Rio Vista
EPA ID: CA4810004 · 10,489 people served · 7 ZIP codes
ZipCheckup's reading of EPA SDWIS for City of Rio Vista (CA4810004): no EPA violations recorded in the last five years. EPA monitoring data for City of Rio Vista shows an unblemished five-year compliance history - no violations of any kind have been recorded for this utility, which supplies water to approximately 10,489 people, covering every reporting cycle without a single MCL exceedance or monitoring lapse.
Data: EPA SDWIS
Service Area Map
Coverage area for City of Rio Vista Source: EPA SDWIS service area boundaries.
Service area boundary - Grade A
Service Area Demographics
The City of Rio Vista serves a community with a median household income of $92,443 and an estimated 135,817 residents across its service area. Approximately 65% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
City of Rio Vista's water is pumped from underground aquifers. Groundwater is naturally filtered through rock and soil, but it can be vulnerable to PFAS contamination, nitrates from agriculture, and industrial chemicals that seep into the water table.
Superfund Proximity Note: This service area ranks in the 63th percentile nationally for proximity to Superfund (NPL) sites. Groundwater sources near contaminated sites may face elevated risk from industrial chemicals.
Infrastructure Risk
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 4 detections recorded. 2 exceed federal EPA limits (4 ppt for PFOA/PFOS). 1 exceeds 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
City of Rio Vista (EPA ID: CA4810004) is a community water system in California that serves approximately 10,489 people from groundwater sources.
This system provides water to 7 ZIP codes across 7 communities.
ZIP-Area Home Safety Context: A (100/100)
This is the average Home Safety Score for 1 of 7 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 |
|---|---|---|
| 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.
- 94512 - Birds Landing
- 94571 - Rio Vista
- 94585 - Suisun City
- 95612 - Clarksburg
- 95620 - Dixon
- 95687 - Vacaville
- 95690 - Walnut Grove
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for City of Rio Vista (CA4810004) on EPA.gov.
Frequently Asked Questions
Is City of Rio Vista water safe to drink?
The accepted 2026Q2 ECHO snapshot contains zero violation records for City of Rio Vista 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 City of Rio Vista serve?
City of Rio Vista serves approximately 10,489 people across 7 ZIP codes in California.
Where does City of Rio Vista get its water?
The primary water source is groundwater.
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 →
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). City of Rio Vista, CA: Serves 10K People. https://zipcheckup.com/water-system/ca4810004/
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title = {{City of Rio Vista, CA: Serves 10K People}},
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url = {https://zipcheckup.com/water-system/ca4810004/}
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