COUNTY REPORT ID

Jefferson County, Idaho

6 ZIP codes · Avg score 69/100 · Grade C · Updated 2026-06-03

Water safety in Jefferson County is uneven — some of its 6 ZIP codes meet standards cleanly while others carry documented violations.

How Jefferson County Compares

Jefferson County69/100
Idaho avg66/100
National avg68/100

How Jefferson County Compares

C
County Grade
69/100
Avg Safety Score
6
ZIP Codes
8
Water Systems

Jefferson County scores 3 points above the Idaho state average (66/100) and 1 points above the national average (68/100).

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

C
County Grade
69
Avg Safety Score
6
ZIP Codes
Best ZIP: 83435 (81/100)
Lowest ZIP: 83425 (53/100)
$217K
Median Home Value
$1,700
Avg Remediation (78% of home value)

ZIP Code Risk Map

Water Quality Map: Jefferson County, Idaho

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: 11.3 (asthma 10.7%, diabetes 9.1%)

Estimated additional annual cost per homeowner: $1,112, driven primarily by energy_code_gap

Infrastructure: 0.37% avg pipe failure probability

62.7% of homes built before 1978 (lead paint era)

Violation History (2021–2024)

→ Stable trend

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

2021
2 (2 health)
2024
2 (2 health)

Peak year: 2021 with 2 violations. Past 5 years: 4 total (4 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 10.7% (national: 8.9%)
Diabetes 9.1% (national: 10.5%)
Obesity 33.1% (national: 32.4%)

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

Infrastructure Overview

1974
Median Build Year
62.7%
Pre-1978 Housing
37%
Pipe Failure Probability
0%
ZIPs at High Infra Risk
Low
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: $1,112

Energy Code Gap $495/yr
Wildfire $300/yr
Flood $167/yr

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

Housing Age Distribution

9,305 housing units in Jefferson County

Pre-1940 10%
1940–1959 10%
1960–1979 22%
1980–1999 17%
2000+ 41%

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 Jefferson County

$217K
Median Home Value
$1,700
Est. Remediation Cost
0.8%
of Home Value
Remediation as % of home value low burden

Remediation costs are relatively manageable for most homeowners in Jefferson 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 Jefferson County residents

Asthma 10.7% (US avg: 8.9%)
Diabetes 9.1% (US avg: 11%)
Obesity 33.1% (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 Jefferson County ranked by EPA violation count.

# Water System Population Violations
1 City of Rigby 5,400 10
2 Morning View Water Company 459 10
3 Country Squire Estates 450 10
4 Pepperwood Crossing/rocky Mnt Utilities 336 10
5 Liberty Estates 300 10

8 total water systems serve Jefferson County.

All ZIP Codes in Jefferson County

6 ZIP codes tracked in Jefferson County.

# ZIP Code City Safety Score Grade Violations Home Value
1 83435 Monteview 81 B 1 $211K
2 83444 Roberts 80 B 3 $181K
3 83442 Rigby 73 B 10 (3 health) $377K
4 83431 Lewisville 63 C 0 $239K
5 83450 Terreton 63 C 0 $184K
6 83425 Hamer 53 D 0 $222K

Recommended Buyer Guides for Jefferson County

Four sources — EPA, NSF, FEMA, CDC — drive the match.

Overview

Jefferson County in Idaho covers 6 ZIP codes with an average Home Safety Score of C (69/100).

3 of 6 ZIP codes have recorded EPA violations. 3 health-based violations have been documented.

← Back to Idaho water quality report

Data Sources

Updated daily.

Frequently Asked Questions

Is water safe in Jefferson County?
Jefferson 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 Jefferson County?
Jefferson County is served by 8 public water systems that supply drinking water to residents across 6 ZIP codes.
What is the biggest environmental risk in Jefferson County?
The primary environmental risk factor in Jefferson County is energy_code_gap. This contributes to an estimated additional annual cost of $1,112 per homeowner.
How old are homes in Jefferson County?
The median home build year in Jefferson County is 1974. 62.7% of homes were built before 1978, which means they may contain lead-based paint and older plumbing materials.
How does Jefferson County compare to Idaho?
Jefferson County has an average water safety score of 69/100, which is above the Idaho state average of 66/100.

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