States › Idaho

Idaho Tap Water Quality 2026

EPA drinking water data for 211 cities across Idaho — covering lead levels, violation history, and compliance status.

Systems tracked: 197 Cities covered: 211 Updated: 2026 Q2
B

Idaho earns a B for overall water quality

211 communities across 44 counties and 197 water systems. 95.7% have no open violations.

Median lead where detected: 2.00 ppb
29.9% of systems report lead as not detected — a state filing convention, not a water quality measure
PFAS tested at 25.1% of communities; 1 above the federal limit
Lead reported for 100.0% of communities
95.7% of communities have no open violations
Water Systems
197
Active community systems
Median Lead Level
2 ppb
13% of EPA action level
Fully Compliant
95.7%
of systems — no active violations
How we grade states Grades are based on actual EPA enforcement data — MCL violations and lead levels measured against the 15 ppb federal action level. We do not use MCLG-based detections, which are aspirational zero-tolerance goals that would make nearly every state look dangerous. Read our full methodology →

Best & Worst Cities in Idaho

✓ Cleanest Water
Coeur d'Alene
Kootenai County
2.0 ppb A
Twin Falls
Twin Falls County
0.0 ppb B
Lewiston
Nez Perce County
1.0 ppb A
Moscow
Latah County
4.0 ppb A
Kuna
Ada County
0.0 ppb A
Chubbuck
Bannock County
2.0 ppb A
⚠ Needs Attention
Juliaetta
Latah County
23.0 ppb F
Reubens
Lewis County
0.0 ppb F
Plummer
Benewah County
1.0 ppb D
Fairfield
Camas County
0.0 ppb D
Worley
Kootenai County
2.0 ppb D
Harrison
Kootenai County
6.0 ppb D

Water Quality by County

44 of 44
Sort:
CountySystemsLead LevelViolationsGrade
Kootenai County 15 2.0 ppb 0 B
Bonner County 12 2.5 ppb 0 A
Latah County 11 3.0 ppb 0 B
Bingham County 9 2.0 ppb 0 A
Ada County 8 2.0 ppb 0 B
Canyon County 8 2.0 ppb 0 A
Idaho County 8 1.5 ppb 0 A
Bannock County 8 2.0 ppb 0 B
Twin Falls County 8 2.8 ppb 0 B
Bear Lake County 6 1.5 ppb 0 A

About Idaho Drinking Water

Idaho is served by 197 community water systems covering 211 communities across 44 counties. 95.7% have no open violation on record.

Lead was detected in 148 communities, with a median of 2.00 ppb — 13% of the federal action level. A further 63 reported none detected. That share is a state reporting convention rather than a measure of water quality, so it is stated separately rather than averaged in.

PFAS has been tested at 25.1% of communities here, and 1 are above the limits EPA set in 2024. Coverage matters: states that test more find more, so this figure is not comparable with a state that has tested less.

Frequently Asked Questions

Is Idaho tap water safe to drink? ▼
95.7% of communities have no open violation on record. 1 have PFAS above the federal limit set in 2024, which is the main open concern.
Does Idaho have a lead problem? ▼
7 water systems report a 90th-percentile lead result at or above the 15 ppb action level. The action level is a treatment trigger, not a legal maximum, and 63 communities report no detection at all.
How complete is the data for Idaho? ▼
Lead results are reported for 100.0% of communities and PFAS for 25.1%. Where a figure is missing it is shown as not reported rather than assumed safe.
How does Idaho compare with other states? ▼
We do not rank states against each other. Lead reporting completeness ranges from under 20% to 100% depending on the state, so a national ranking would compare filing practice rather than water quality.