Idaho Water Quality Rankings 2026

All 20 cities ranked by water quality score

State Average78/100

Cities Ranked

Coeur d'Alene

Best City (95/100)

Eagle

Lowest Score (66/100)

60%

Above National Avg

Grade Distribution

How Idaho's 20 cities are distributed by water quality grade

A Range

30% of cities

B Range

55% of cities

C Range

15% of cities

0% of cities

Cities with good water quality (B or better)55%

11 out of 20 cities meet or exceed a B grade for water quality

All 20 Idaho Cities Ranked

Sorted by water quality score from best to worst. Click any city for a detailed water quality report.

Rank	City	Score	Grade	Population	Top Concern
1	Coeur d'Alene	95/100	A+	54,628	None identified
2	Rexburg	93/100	A	31,441	None identified
3	Pocatello	91/100	A	56,320	None identified
#4	Post Falls	87/100	A-	38,485	None identified
#5	Chubbuck	86/100	A-	15,570	None identified
#6	Mountain Home	86/100	A-	14,308	None identified
#7	Caldwell	83/100	B+	59,996	None identified
#8	Boise	80/100	B+	235,684	None identified
#9	Moscow	80/100	B+	26,047	None identified
#10	Idaho Falls	79/100	B	64,818	None identified
#11	Jerome	77/100	B	12,137	None identified
#12	Twin Falls	74/100	B-	51,807	None identified
#13	Nampa	72/100	B-	100,200	None identified
#14	Garden City	71/100	B-	12,329	None identified
#15	Kuna	71/100	B-	24,011	None identified
#16	Lewiston	71/100	B-	34,203	None identified
#17	Ammon	70/100	B-	17,694	None identified
#18	Meridian	67/100	C+	117,635	None identified
#19	Blackfoot	66/100	C+	12,346	None identified
#20	Eagle	66/100	C+	31,384	None identified

Key Findings

The best water quality in Idaho is found in Coeur d'Alene with a score of 95/100 and a grade of A+. This puts Coeur d'Alene among the top-performing cities in the country for drinking water safety.

The most concerning water quality is in Eagle scoring 66/100 with a grade of C+. Residents may want to consider home water testing and filtration options.

The statewide average score is 78/100, which is 6 points above the national average of 72/100. Over half (60%) of Idaho cities score above the national average, though some areas face challenges.

Frequently Asked Questions

Which city in Idaho has the best water quality?

Coeur d'Alene has the best water quality in Idaho with a score of 95/100 and a grade of A+. This score is based on contaminant levels, EPA compliance history, and infrastructure quality. Coeur d'Alene ranks among the top cities nationally for water quality.

Is Idaho tap water safe to drink?

Water quality varies across Idaho. The state average score is 78/100. 55% of Idaho cities have good water quality (grade B or better). All cities in Idaho maintain at least a C-grade, though individual results can vary by neighborhood and home plumbing. Always check your specific city's water quality report for the most accurate local information.

How many Idaho cities have water quality concerns?

Of the 20 cities tracked in Idaho, 0 cities have a D or F grade, indicating significant water quality concerns. An additional 3 cities fall in the C range, suggesting moderate issues. 12 out of 20 cities (60%) score above the national average of 72/100. Residents concerned about their water quality can check their city's detailed report for specific contaminant information.