Idaho Water Quality Report
Tap water quality data for 3 cities in Idaho, updated 2026.
US average: 100 ppm
2 of 3 cities violation-free
3 cities tested
3 water systems tracked
Cleanest Tap Water in Idaho
Cities with the fewest water quality issues
Most Water Quality Issues in Idaho
Cities with the most violations and concerns
Water Hardness Across Idaho
Not sure what your hardness means? Use our Water Hardness Calculator or find the best hardness test kits.
Idaho Tap Water: What You Need to Know
Idaho has 3 tracked water utilities serving approximately 508K residents. The average water hardness is 159 ppm (9.3 GPG), classified as Hard — above the national average of 100 ppm. Hardness ranges from 157.6 ppm in Meridian to 163 ppm in Nampa City of.
In the past 3 years, 1 of 3 cities in Idaho have recorded water quality violations, totaling 3 violations (0 health-based). All 3 tested cities have lead levels below the EPA action level of 15 ppb.
With hard water on average, many Idaho residents may notice mineral buildup on fixtures, dry skin, or stiff-feeling hair. A shower filter for hard water can help reduce chlorine exposure, while a water softener addresses the mineral buildup directly.
Frequently Asked Questions About Idaho Water
Is tap water safe to drink in Idaho?
Most tap water in Idaho meets EPA standards, but 1 cities have recorded violations in the past 3 years (0 health-based). We recommend checking your specific city's report on TapWater.org and considering a home water test.
How hard is the water in Idaho?
Idaho's average water hardness is 159 ppm (9.3 GPG), classified as Hard. This is above the national average of 100 ppm. Hardness varies significantly by city — use our Water Hardness Calculator to check your specific area.
Which city in Idaho has the cleanest tap water?
Based on EPA violation data, lead testing, and water quality metrics, Veolia ranks as having the cleanest tap water in Idaho. It has zero violations in the past 3 years and lead levels well below the EPA action level.
Which city in Idaho has the most water quality issues?
Nampa City of currently has the most water quality concerns in Idaho, with 3 violations in the past 3 years. Residents should check their city's detailed water quality report and consider using a certified water filter.
Where does Idaho get its water from?
The majority of Idaho's water systems (33%) use surface water as their primary source. Surface water comes from rivers, lakes, and reservoirs. Each city's specific source can vary — check individual city reports for details.