Mission Highlands Mutual Water Company
EPA ID: CA4900563 · 150 people served · 1 ZIP code
ZipCheckup's reading of EPA records for Mission Highlands Mutual Water Company (CA4900563): 1 violation on record since 2021. While 1 violation did appear in Mission Highlands Mutual Water Company's monitoring record, none is listed as unresolved; the utility serves approximately 150 residents. A closed violation record does not by itself establish compliance with every current EPA standard.
Data: EPA SDWIS
Service Area Map
Coverage area for Mission Highlands Mutual Water Company Source: EPA SDWIS service area boundaries.
Service area boundary
Demographics of ZIP Codes Served
The ZIP codes associated with Mission Highlands Mutual Water Company have a median household income of $108,322 and about 35,139 residents live in those ZIP codes (Census; not the number of people this system supplies). Approximately 69% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
💧 Where Does Your Water Come From?
Mission Highlands Mutual Water Company's water is classified in EPA records as a groundwater source. 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 in ZIP Codes This System Serves
PFAS ("forever chemicals") have been reported in samples from water systems associated with the ZIP codes in this system's area. These results can come from other water systems serving the same ZIP codes; check the UCMR5 section for any results reported for this system. 6 detections recorded. 2 detections are above the level of a federal PFAS MCL (4 ppt for PFOA and PFOS), with compliance required from 2029.
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
Mission Highlands Mutual Water Company (EPA ID: CA4900563) is a community water system in California that serves approximately 150 people from groundwater sources.
This system serves ZIP code 95476 in Sonoma.
Violation History
Status breakdown for accepted records with record years 2021-2026: 1 resolved, 0 archived, 0 addressed, and 0 unaddressed. Under this source contract, current noncompliance is the sum of addressed and unaddressed records. Archived and resolved records are excluded from current noncompliance.
Recent Violations
| Date | Contaminant | Type | Status |
|---|---|---|---|
| May 1, 2021 | Revised Total Coliform Rule | Non-health-based | Resolved |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Revised Total Coliform Rule | Monitoring & Reporting | 1 | No |
Lead & Copper
EPA Lead and Copper Rule evidence attributed directly to this water system:
| Lead Level | Exceeds Action Level | Sample Date |
|---|---|---|
| Below the reporting limit | No | 2023-12-31 |
No copper action-level exceedance record appears for this PWSID in the accepted LCR snapshot. This does not establish a clean copper measurement.
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: Ask your water utility whether running cold water for 2 minutes is enough to flush your plumbing before drinking.
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.
- 95476 - Sonoma
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View available EPA compliance records for Mission Highlands Mutual Water Company (CA4900563) on EPA.gov.
Frequently Asked Questions
Is Mission Highlands Mutual Water Company water safe to drink?
The accepted 2026Q2 ECHO snapshot shows no current noncompliance for Mission Highlands Mutual Water Company; its 1 accepted 2021-2026 record are resolved or archived. Historical compliance status does not establish conditions at a specific tap.
How many people does Mission Highlands Mutual Water Company serve?
Mission Highlands Mutual Water Company serves approximately 150 people across 1 ZIP code in California.
Where does Mission Highlands Mutual Water Company get its water?
The primary water source is groundwater.
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). Mission Highlands Mutual Water Company (CA): 1 EPA Violation. https://zipcheckup.com/water-system/ca4900563/
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author = {{ZipCheckup}},
title = {{Mission Highlands Mutual Water Company (CA): 1 EPA Violation}},
year = {n.d.},
url = {https://zipcheckup.com/water-system/ca4900563/}
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What You Can Do
Test your water
Home test kits can detect lead, bacteria, and other contaminants at your tap. Find the right filter →
Check your specific ZIP code
Water quality can vary within a system. View nearest ZIP report →
Contact your utility
Mission Highlands Mutual Water Company (EPA ID: CA4900563) - request the latest Consumer Confidence Report or ask about specific contaminants.