San Joaquin County-mokelumne Acres
EPA ID: CA3910017 · 3,802 people served · 4 ZIP codes
ZipCheckup's reading of EPA SDWIS for San Joaquin County-mokelumne Acres (CA3910017): PFAS sampling above the current EPA limit (UCMR5). Five years of EPA monitoring have produced no violations for San Joaquin County-mokelumne Acres - the supplier serving 3,802 residents has kept every contaminant level within federal limits, a result that places it among the top-performing utilities for systems with a service population of comparable size.
Data: EPA SDWIS
Service Area Map
Coverage area for San Joaquin County-mokelumne Acres Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The San Joaquin County-mokelumne Acres serves a community with a median household income of $108,926 and an estimated 107,025 residents across its service area. Approximately 45% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: 55% 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?
San Joaquin County-mokelumne Acres'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.
Superfund Proximity Note: This service area ranks in the 70th percentile nationally for proximity to Superfund (NPL) sites. Groundwater sources near contaminated sites may face elevated risk from industrial chemicals.
Infrastructure Risk
PFAS Detected in Service Area
PFAS ("forever chemicals") have been detected in water serving this system's area. 4 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
San Joaquin County-mokelumne Acres (EPA ID: CA3910017) is a community water system in California that serves approximately 3,802 people from groundwater sources.
This system provides water to 4 ZIP codes across 3 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 San Joaquin County-mokelumne Acres (CA3910017) on EPA.gov.
Frequently Asked Questions
Is San Joaquin County-mokelumne Acres water safe to drink?
The accepted 2026Q2 ECHO snapshot contains zero violation records for San Joaquin County-mokelumne Acres 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 San Joaquin County-mokelumne Acres serve?
San Joaquin County-mokelumne Acres serves approximately 3,802 people across 4 ZIP codes in California.
Where does San Joaquin County-mokelumne Acres get its water?
The primary water source is groundwater.
Federal UCMR5 PFAS Monitoring: Above Current MCL
This water system was tested under the federal EPA Unregulated Contaminant Monitoring Rule (UCMR5). One or more PFAS compounds were measured above the current state-enforceable MCL.
Current MCL reflects the lowest state-enforceable limit (NYS 10 ppt for PFOA/PFOS, effective August 2020). The federal final MCL of 4 ppt for PFOA/PFOS (EPA April 2024 rule) is not enforceable until April 2029. Detections above 4 ppt but below 10 ppt are below current MCL but above the future federal limit.
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.). San Joaquin County-mokelumne Acres Water Quality Report, CA. https://zipcheckup.com/water-system/ca3910017/
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