Diamond a Mutual Water Company
EPA ID: CA4900562 · 640 people served · 1 ZIP code
ZipCheckup's reading of EPA SDWIS for Diamond a Mutual Water Company (CA4900562): 2 unresolved EPA violations on record. Five-year compliance data for Diamond a Mutual Water Company includes 2 violations the EPA has not yet marked resolved - those open findings are part of the utility's current enforcement profile, covering a service population of approximately 640 residents across the area it supplies.
Data: EPA SDWIS
Service Area Map
Coverage area for Diamond a Mutual Water Company Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Diamond a Mutual Water Company serves a community with a median household income of $108,322 and an estimated 35,139 residents across its service area. 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?
Diamond a Mutual Water Company'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
Detected Contaminants
How Diamond a Mutual Water Company compares to EPA limits
What This Means For You
Stage 2 DBP Rule at 2 mg/L exceeds the EPA maximum of mg/L.
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 6 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
Diamond a Mutual Water Company (EPA ID: CA4900562) is a community water system in California that serves approximately 640 people from groundwater sources.
This system serves ZIP code 95476 in Sonoma.
Violation History
Status breakdown for accepted records with record years 2021-2026: 0 resolved, 0 archived, 0 addressed, and 2 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 |
|---|---|---|---|
| October 17, 2024 | Stage 2 DBP Rule | Non-health-based | Unaddressed (current) |
| October 17, 2024 | Stage 2 DBP Rule | Health-based | Unaddressed (current) |
Contaminants Detected
The following contaminants have been flagged in EPA records for this water system:
| Contaminant | Category | Violations | Health-Based |
|---|---|---|---|
| Stage 2 DBP Rule | Treatment Failure | 2 | Yes |
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.
- 95476 - Sonoma
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Diamond a Mutual Water Company (CA4900562) on EPA.gov.
Frequently Asked Questions
Is Diamond a Mutual Water Company water safe to drink?
The accepted 2026Q2 ECHO snapshot shows 1 current health-based noncompliance record for Diamond a Mutual Water Company. Review the utility's current notices and EPA record. This system-level compliance history cannot determine conditions at a specific tap.
How many people does Diamond a Mutual Water Company serve?
Diamond a Mutual Water Company serves approximately 640 people across 1 ZIP code in California.
Where does Diamond a Mutual Water Company get its water?
The primary water source is groundwater.
Frequently Asked Questions
How to cite this page
ZipCheckup. (n.d.). Diamond a Mutual Water Company (CA): 1 Health Violation. https://zipcheckup.com/water-system/ca4900562/
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author = {{ZipCheckup}},
title = {{Diamond a Mutual Water Company (CA): 1 Health Violation}},
year = {n.d.},
url = {https://zipcheckup.com/water-system/ca4900562/}
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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
Diamond a Mutual Water Company (EPA ID: CA4900562) - request the latest Consumer Confidence Report or ask about specific contaminants.