Water Quality in Mariposa, CA (95338)
EPA violation data for public water systems serving ZIP code 95338.
Active Health Violations
2 health-based violations found in the past 5 years, with at least one still unresolved. Contaminant levels have exceeded federal safety limits. Consider testing your tap water independently.
More violations than 72% of US ZIP codes.
Based on EPA compliance data. Not a substitute for an official water quality report from your utility.
10,006
Population
76
Water Systems
14
Violations (5yr)
2
Health-Based
Location
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Water Systems Serving This Area (76)
Mariposa Public Utility Dist
Surface water 2,000 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
Bagby Recreational Area
Groundwater 1,000 people served
0 violations
Mariposa County Fairground
Groundwater 1,000 people served
0 violations
Ponderosa Basin Mutual Wtr Co
Groundwater 798 people served
1 violation (5yr)
Lead tested: 0 ppb (limit: 15 ppb) ✓
Greenameyer Brothers Water Sy
Groundwater 500 people served
0 violations
Greenamyers Bros Water Sys
Groundwater 500 people served
0 violations
Frank Lemelin
Surface water 500 people served
0 violations
Musd - Woodland Elementary School
Groundwater 466 people served
0 violations
Coarsegold School
Groundwater 441 people served
0 violations
Lead tested: 14 ppb (limit: 15 ppb) ✓
Yosemite West Water System
Groundwater 420 people served
0 violations
Coulterville County Service
Groundwater 300 people served
0 violations
Mariposa Pines Mutual
1 health-based Groundwater 284 people served
3 violations (5yr)
· 1 health-based
Lead tested: 0 ppb (limit: 15 ppb) ✓
Woodland Elementary School
Groundwater 255 people served
0 violations
Woodland Elementary School
Groundwater 255 people served
0 violations
Mcpr-Cathey S Valley Park
Groundwater 250 people served
0 violations
Ronald Hiser
Groundwater 200 people served
0 violations
New Life Christian Fellowship
Groundwater 200 people served
0 violations
Mariposa Pines Mutual Water Co
Groundwater 200 people served
0 violations
Mariposa District Fairground
Groundwater 200 people served
0 violations
Mariposa Unified School Dist
Groundwater 200 people served
0 violations
Mpwd-Coulterville Csa 1
All resolved Groundwater 193 people served
1 violation (5yr)
· All resolved
Lead tested: 1.4 ppb (limit: 15 ppb) ✓
Musd - Sierra Foothill Charter School
Purchased surface water 157 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
Mariposa County Unified
Groundwater 150 people served
0 violations
Greeley Hill Elementary School
Groundwater 140 people served
0 violations
Musd - Mariposa Junior High School
Groundwater 134 people served
0 violations
Lead tested: 0 ppb (limit: 15 ppb) ✓
Little Church In The Hills
Groundwater 125 people served
0 violations
Mt Bullion
Groundwater 104 people served
0 violations
Mt Bullion Youth Conservation
Groundwater 104 people served
0 violations
Mt Bullion Youth Conserv Camp
Groundwater 104 people served
0 violations
N Wawona Park
Groundwater 100 people served
0 violations
Wildhaven Yosemite Water System
Groundwater 100 people served
0 violations
Mariposa Pines Mutual Water Co
Groundwater 80 people served
0 violations
Spring Hill School
Groundwater 80 people served
0 violations
Lushmeadows Barn
Groundwater 70 people served
0 violations
Lushmeadows Barn
Groundwater 70 people served
0 violations
Bootjack Stompers Hall
Groundwater 60 people served
0 violations
Mariposa Lutheran Church
Groundwater 60 people served
0 violations
Mrs Carmen Holmes
Groundwater 60 people served
0 violations
Cdf & Fp - Mt. Bullion
Groundwater 60 people served
0 violations
Lead tested: 18 ppb (limit: 15 ppb)
Mariposa Industrial Park Water Company
All resolved Groundwater 60 people served
4 violations (5yr)
· All resolved
Mrs Carmen Holmes
Groundwater 60 people served
0 violations
Musd -Coulterville - Greeley Hill School
Groundwater 55 people served
0 violations
Lead tested: 5.4 ppb (limit: 15 ppb) ✓
Mariposa County Public Works Department
Groundwater 55 people served
0 violations
Lead tested: 92 ppb (limit: 15 ppb)
Hummingbird Ent
Groundwater 52 people served
0 violations
Woodland Market Company
Groundwater 52 people served
0 violations
Tavis Corporation
1 health-based Groundwater 50 people served
4 violations (5yr)
· 1 health-based
Lead tested: 7 ppb (limit: 15 ppb) ✓
Sierra Garden Apartments
Groundwater 50 people served
0 violations
Mcpr - Darrah School Park
Groundwater 50 people served
0 violations
Mcpr-Midpines Park
Groundwater 50 people served
0 violations
Tavis Corporation
Groundwater 50 people served
0 violations
Triangle Market
Groundwater 50 people served
0 violations
Catheys Valley School
Groundwater 50 people served
0 violations
Hunter'S Point Marina
Groundwater 50 people served
0 violations
Usona Corporation
Groundwater 50 people served
0 violations
Tavis Corporation
Groundwater 50 people served
0 violations
Covanta Delano, Inc.
Groundwater 46 people served
0 violations
Cruz & Willies
Groundwater 40 people served
0 violations
Catheys Valley
Groundwater 40 people served
0 violations
Whispering Pines Motel
Groundwater 40 people served
0 violations
Musd- Spring Hill Facility
Groundwater 40 people served
0 violations
Mcpr- Woodland Park
All resolved Groundwater 35 people served
1 violation (5yr)
· All resolved
Lead tested: 0.7 ppb (limit: 15 ppb) ✓
Parker'S Water System
Groundwater 30 people served
0 violations
Mariposa Manor
Groundwater 30 people served
0 violations
Acorn Cooperative Preschool
Groundwater 30 people served
0 violations
Hubert L Heipe, Owner
Groundwater 30 people served
0 violations
Mariposa Pines Villa
Groundwater 28 people served
0 violations
Crystal Aire
Groundwater 28 people served
0 violations
Butterfly Montessori School
Groundwater 27 people served
0 violations
Airport Inn
Groundwater 26 people served
0 violations
Ca. Dept. Of Forestry, Hornitos
Groundwater 25 people served
0 violations
Mcpr-Hornitos Co. Park
Groundwater 25 people served
0 violations
Mel O Dee Motel
Groundwater 25 people served
0 violations
Ca. Dept Of Forestry, Coulterville
Groundwater 25 people served
0 violations
Mcpr-Red Cloud Park
Groundwater 25 people served
0 violations
Cedar Grove Bible Camp
Groundwater 25 people served
0 violations
Sierra Garden Apartments
Groundwater 0
0 violations
Contaminants Found
LEAD AND COPPER RULE REVISIONSHealth-Based
4 violations
Has active
Lead and Copper RuleMonitoring
Lead and copper testing requirement. Lead exposure can cause developmental harm in children.
2 violations
Has active
Consumer Confidence RuleMonitoring
Annual water quality report delivery requirement.
2 violations
All resolved
Revised Total Coliform RuleMonitoring
Missed testing deadlines — not a detection of bacteria.
2 violations
All resolved
Total Haloacetic Acids (HAA5)Monitoring
2 violations
All resolved
TTHMMonitoring
2 violations
All resolved
Lead & Copper Levels
Lead (Pb)
Within limit0 ppb measured
Action level: 15 ppb
Sampled: Jan 2025
How Does This Compare?
Mariposa (95338) has more violations than 72% of US ZIP codes. The national average is 18.87 violations per ZIP over 5 years. This ZIP has 14.
Fewer violations 72th percentile More violations
Recommended Water Filters
Based on health-based violations detected in your area, these filter types are commonly used to address similar contaminants. Consult your water utility's Consumer Confidence Report for the most current data.
Reverse Osmosis System
Highly effective at removing heavy metals, dissolved solids, and a wide range of contaminants. Recommended for homes with lead or arsenic concerns.
Targets:Lead, Copper, Arsenic, Mercury, Cadmium
Look for:NSF/ANSI 58 certified
Always look for filters certified by NSF International for the specific contaminants you want to remove. This is general educational information, not an endorsement of any specific product.