Yosemite West Water System
EPA ID: CA2210924 · 420 people served · 1 ZIP code
Federal monitoring spanning five full years has produced zero violations at Yosemite West Water System — a clean record across every reporting cycle for a utility serving approximately 420 residents.
Data: EPA SDWIS Last verified: 2026-04-02
Service Area Map
Coverage area for Yosemite West Water System Source: EPA SDWIS service area boundaries.
Service area boundary
Service Area Demographics
The Yosemite West Water System serves a community with a median household income of $64,707 and an estimated 10,164 residents across its service area. Approximately 54% of housing stock was built before 1986, which increases the likelihood of lead service lines and older plumbing.
Environmental Justice Note: 50% 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?
Yosemite West Water System'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.
About 3% of homes in Mariposa 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
Yosemite West Water System (EPA ID: CA2210924) is a community water system in California that serves approximately 420 people from groundwater sources.
This system serves ZIP code 95338 in Mariposa.
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
- 95338 — Mariposa
Data Sources
This report uses public data from the EPA Safe Drinking Water Information System (SDWIS). View the full compliance record for Yosemite West Water System (CA2210924) on EPA.gov.
Frequently Asked Questions
Is Yosemite West Water System water safe to drink?
Based on EPA records, Yosemite West Water System has no recorded violations in the past 5 years — a positive indicator of water quality management.
How many people does Yosemite West Water System serve?
Yosemite West Water System serves approximately 420 people across 1 ZIP code in California.
Where does Yosemite West Water System get its water?
The primary water source is groundwater.
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.