Circle Oaks Water District
EPA ID: CA2800521 · 500 people served · 3 ZIP codes
Water monitoring for Circle Oaks Water District: clean, five years, 500 residents.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Circle Oaks Water District Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Circle Oaks Water District serves a community with a median household income of $105,002 and an estimated 92,380 residents across its service area. Approximately 72% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Circle Oaks 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 2% of homes in Napa 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
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
Circle Oaks Water District (EPA ID: CA2800521) is a community water system in California that serves approximately 500 people from surface water sources.
This system provides water to 3 ZIP codes across 1 community.
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
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Circle Oaks Water District (CA2800521) on EPA.gov.
Frequently Asked Questions
Is Circle Oaks Water District water safe to drink?
Based on EPA records, Circle Oaks Water District has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Circle Oaks Water District serve?
Circle Oaks Water District serves approximately 500 people across 3 ZIP codes in California.
Where does Circle Oaks Water District get its water?
The primary water source is surface water.
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.