Rio Alto Water District
EPA ID: CA5210005 · 3,329 people served · 2 ZIP codes
ZipCheckup's reading of EPA SDWIS for Rio Alto Water District (CA5210005): no EPA violations recorded in the last five years. Throughout five consecutive years of federal water monitoring, Rio Alto Water District recorded zero violations - solid performance for a utility serving 3,329 people.
Data: EPA SDWIS
Service Area Map
Coverage area for Rio Alto Water District Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Rio Alto Water District serves a community with a median household income of $75,293 and an estimated 47,646 residents across its service area. Approximately 54% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: 100% 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?
Rio Alto Water District'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.
Infrastructure Risk
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 4 detections recorded. 1 exceeds 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
Rio Alto Water District (EPA ID: CA5210005) is a community water system in California that serves approximately 3,329 people from groundwater sources.
This system provides water to 2 ZIP codes across 2 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.
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 Rio Alto Water District (CA5210005) on EPA.gov.
Frequently Asked Questions
Is Rio Alto Water District water safe to drink?
The accepted 2026Q2 ECHO snapshot contains zero violation records for Rio Alto 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 Rio Alto Water District serve?
Rio Alto Water District serves approximately 3,329 people across 2 ZIP codes in California.
Where does Rio Alto Water District get its water?
The primary water source is groundwater.
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). Rio Alto Water District Water Quality Report, CA. https://zipcheckup.com/water-system/ca5210005/
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