Coastside County Water District
EPA ID: CA4110011 · 18,940 people served · 5 ZIP codes
ZipCheckup's reading of EPA records for Coastside County Water District (CA4110011): no drinking-water violations recorded since 2021. Zero violations are listed in EPA monitoring data for Coastside County Water District; a count of records like this is not a water-quality test for the 18,940 residents it serves.
Data: EPA SDWIS
Service Area Map
Coverage area for Coastside County Water District Source: EPA SDWIS service area boundaries.
Service area boundary
Demographics of ZIP Codes Served
The ZIP codes associated with Coastside County Water District have a median household income of $191,758 and about 89,912 residents live in those ZIP codes (Census; not the number of people this system supplies). Approximately 76% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
🌊 Where Does Your Water Come From?
Coastside County 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.
Superfund Proximity Note: This service area ranks in the 60th percentile nationally for proximity to Superfund (NPL) sites.
Infrastructure Risk
Comparable Water Systems
Similar-sized systems in California
System Overview
Coastside County Water District (EPA ID: CA4110011) is a community water system in California that serves approximately 18,940 people from surface water sources.
This system provides water to 5 ZIP codes across 5 communities.
Violation History
Lead & Copper
EPA Lead and Copper Rule evidence attributed directly to this water system:
| Lead Level | Exceeds Action Level | Sample Date |
|---|---|---|
| 0.0016 mg/L | No | 2024-12-31 |
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
5 of 5 ZIP records with known zones are in EPA Radon Zone 2.
The EPA recommends testing all homes regardless of radon zone. County radon zones cannot replace an in-home radon test.
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 available EPA compliance records for Coastside County Water District (CA4110011) on EPA.gov.
Frequently Asked Questions
Is Coastside County Water District water safe to drink?
The accepted 2026Q2 ECHO snapshot contains zero violation records for Coastside County 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 Coastside County Water District serve?
Coastside County Water District serves approximately 18,940 people across 5 ZIP codes in California.
Where does Coastside County Water District get its water?
The primary water source is surface water.
Federal UCMR5 PFAS Monitoring: No PFAS Reported Above Reporting Levels
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). No PFAS compounds were reported above UCMR5 minimum reporting levels.
EPA's April 2024 PFAS rule sets MCLs of 4 ppt for PFOA and PFOS and 10 ppt for PFHxS, PFNA and HFPO-DA (GenX); water systems must comply from 2029. Other PFAS compounds have no individual federal MCL. A state standard is shown only where this system's state has its own enforceable PFAS limit. Detection results are EPA UCMR5 samples, not a measurement at your tap.
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.). Coastside County Water District, CA: Serves 19K People. https://zipcheckup.com/water-system/ca4110011/
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