COUNTY REPORT CA

Mono County, California

6 ZIP codes · Avg score 68/100 · Grade C · Updated 2026-06-03

Tracking 6 ZIP codes in Mono County reveals a mixed picture — tap water quality varies meaningfully by location.

How Mono County Compares

Mono County68/100
California avg73/100
National avg68/100

How Mono County Compares

C
County Grade
68/100
Avg Safety Score
6
ZIP Codes
13
Water Systems

Mono County scores 5 points below the California state average (73/100) and 0 points above the national average (68/100).

Data: EPA SDWIS Last verified: 2026-06-03

C
County Grade
68
Avg Safety Score
6
ZIP Codes
Best ZIP: 93517 (79/100)
Lowest ZIP: 96133 (53/100)
$371K
Median Home Value
$1,500
Avg Remediation (40% of home value)

ZIP Code Risk Map

Water Quality Map: Mono County, California

Each dot represents a ZIP code. Color indicates water quality grade. Tap a dot for details.

A B C D F

Key Risk Factors

Health risk index: 11.8 (asthma 9.9%, diabetes 10.5%)

Estimated additional annual cost per homeowner: $1,473, driven primarily by energy_code_gap

Infrastructure: 0.398% avg pipe failure probability, 50% of ZIPs at high risk

72.2% of homes built before 1978 (lead paint era)

Violation History (2021–2024)

→ Stable trend

EPA violation counts by year across Mono County water systems. Health-based shown in red, total in blue.

2021
2 (2 health)
2023
2 (2 health)
2024
6 (6 health)

Peak year: 2024 with 6 violations. Past 5 years: 10 total (10 health-based).

Source: EPA SDWIS historical violations. Data may lag 6–12 months for the most recent year.

County Health Indicators vs National Average

Asthma 9.9% (national: 8.9%)
Diabetes 10.5% (national: 10.5%)
Obesity 31.2% (national: 32.4%)

Black markers indicate national averages. Source: CDC PLACES, Census ACS.

Infrastructure Overview

1973
Median Build Year
72.2%
Pre-1978 Housing
40%
Pipe Failure Probability
50%
ZIPs at High Infra Risk
High
Lead Pipe Risk

Sources: Census ACS (housing age), EPA SDWIS (infrastructure risk model), state bridge inspection data.

Compound Risk Breakdown

Estimated additional annual cost per homeowner: $1,473

Energy Code Gap $540/yr
Flood $400/yr
Wildfire $300/yr

Bar widths proportional to share of total annual risk cost. Source: compound risk model (FEMA, EPA, USGS).

Housing Age Distribution

8,885 housing units in Mono County

Pre-1940 11%
1940–1959 12%
1960–1979 36%
1980–1999 31%
2000+ 10%

Source: U.S. Census Bureau ACS B25034 (Year Structure Built).

Water Safety Affordability

How much it costs to fix water issues relative to home values in Mono County

$371K
Median Home Value
$1,500
Est. Remediation Cost
0.4%
of Home Value
Remediation as % of home value low burden

Remediation costs are relatively manageable for most homeowners in Mono County, representing a small fraction of property value.

Remediation includes water filtration, lead abatement, radon mitigation, and flood protection where applicable. Source: Census ACS, EPA SDWIS.

Health Outcomes vs National Average

CDC PLACES data for Mono County residents

Asthma 9.9% (US avg: 8.9%)
Diabetes 10.5% (US avg: 11%)
Obesity 31.2% (US avg: 32.4%)

Black markers = national averages. Red = above national avg. Green = below. Source: CDC PLACES, Census ACS.

Water Systems with Most Violations

Top 5 systems in Mono County ranked by EPA violation count.

# Water System Population Violations
1 June Lake Pud - Down Canyon 2,810 7
2 June Lake Pud Village 2,763 7
3 Usmc/mtn Warfare Trng Ctr - Bridgeport 1,200 5
4 Bridgeport Pud 524 5
5 Usmc - Housing Coleville 424 5

13 total water systems serve Mono County.

All ZIP Codes in Mono County

6 ZIP codes tracked in Mono County.

# ZIP Code City Safety Score Grade Violations Home Value
1 93517 Bridgeport 79 B 5 (1 health) $321K
2 93514 Bishop 71 B 3 (1 health) $435K
3 93541 Lee Vining 71 B 0 $334K
4 96107 Coleville 71 B 5 (3 health) $371K
5 93529 June Lake 63 C 7 (4 health) $706K
6 96133 Topaz 53 D 0

Recommended Buyer Guides for Mono County

Eight risk categories drive the selection — PFAS exceedance, lead above EPA action level, pre-1978 housing share, EPA Radon Zone 1, flood-top-risk, wildfire-top-risk, multi-contaminant load, and a baseline fallback — and each category maps to a specific buyer-guide track that surfaces when the county data hits its threshold for that hazard signal.

Overview

Mono County in California covers 6 ZIP codes with an average Home Safety Score of C (68/100).

4 of 6 ZIP codes have recorded EPA violations. 9 health-based violations have been documented.

← Back to California water quality report

Data Sources

Updated daily.

Frequently Asked Questions

Is water safe in Mono County?
Mono County receives a grade of C. Some ZIP codes have recorded violations and residents in affected areas may want to test their water.
How many water systems serve Mono County?
Mono County is served by 13 public water systems that supply drinking water to residents across 6 ZIP codes.
What is the biggest environmental risk in Mono County?
The primary environmental risk factor in Mono County is energy_code_gap. This contributes to an estimated additional annual cost of $1,473 per homeowner.
How old are homes in Mono County?
The median home build year in Mono County is 1973. 72.2% of homes were built before 1978, which means they may contain lead-based paint and older plumbing materials.
How does Mono County compare to California?
Mono County has an average water safety score of 68/100, which is below the California state average of 73/100.

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