PFAS in Idaho Drinking Water
Ranked by number of PFAS compounds detected · Data from EPA SDWIS & UCMR
PFAS in Idaho: what the data shows
Idaho has 51 cities with PFAS monitoring data from the EPA's UCMR 5 program. PFAS ("forever chemicals") were detected in 37 of those cities (73%), with some cities exceeding the EPA's 2024 maximum contaminant levels of 4 ppt. The state average is better than the national average. 3 cities exceed the EPA MCL for at least one PFAS compound. PFAS are linked to cancer, immune system disruption, and developmental issues. The 2024 EPA rule requires water systems exceeding the MCL to notify customers and reduce levels by 2029. PFAS data comes from the EPA's Unregulated Contaminant Monitoring Rule 5 (UCMR 5), which required large water systems to test for 29 PFAS compounds between 2023–2025. Not all systems have completed testing — cities without data may still have PFAS present.
Cities exceeding EPA MCL (4 ppt each)
PFAS data across Idaho
Each dot is a city, colored by overall water quality grade. PFAS-tested cities are shown; those exceeding the 4 ppt EPA MCL appear in red. Size reflects population served.
Top 10 cities by pfas level in Idaho
Highest PFAS levels (compounds)
All Idaho cities ranked by pfas level
| # | City | Level | Level | Exceeds? | Violations | Grade |
|---|---|---|---|---|---|---|
| 1 | Boise | 8 compounds | Yes | 218 | F | |
| 2 | Garden City | 8 compounds | Yes | 12 | C- | |
| 3 | Lewiston | 4 compounds | No | 91 | F | |
| 4 | Mountain Home Afb | 4 compounds | No | 17 | D | |
| 5 | Meridian | 3 compounds | Yes | 34 | F | |
| 6 | Payette | 3 compounds | No | 8 | B | |
| 7 | Rathdrum | 2 compounds | No | 79 | D | |
| 8 | Shelley | 2 compounds | No | 44 | D | |
| 9 | Nampa | 1 compounds | No | 255 | F | |
| 10 | Idaho Falls | 1 compounds | No | 101 | D | |
| 11 | Caldwell | 1 compounds | No | 226 | F | |
| 12 | Pocatello | 1 compounds | No | 117 | F | |
| 13 | Twin Falls | 1 compounds | No | 71 | D+ | |
| 14 | Rexburg | 1 compounds | No | 83 | F | |
| 15 | Kuna | 1 compounds | No | 98 | D | |
| 16 | Ammon | 1 compounds | No | 52 | D+ | |
| 17 | Chubbuck | 1 compounds | No | 16 | C+ | |
| 18 | Star | 1 compounds | No | 0 | A | |
| 19 | Middleton | 1 compounds | No | 64 | D+ | |
| 20 | Jerome | 1 compounds | No | 22 | D | |
| 21 | Blackfoot | 1 compounds | No | 85 | F | |
| 22 | Eagle | 1 compounds | No | 52 | F | |
| 23 | Burley | 1 compounds | No | 29 | F | |
| 24 | Rigby | 1 compounds | No | 28 | D | |
| 25 | Emmett | 1 compounds | No | 31 | D | |
| 26 | Franklin | 1 compounds | No | 13 | C+ | |
| 27 | Rupert | 1 compounds | No | 5 | D+ | |
| 28 | Weiser | 1 compounds | No | 0 | A- | |
| 29 | American Falls | 1 compounds | No | 36 | F | |
| 30 | Ketchum | 1 compounds | No | 34 | D | |
| 31 | Buhl | 1 compounds | No | 65 | D | |
| 32 | St Anthony | 1 compounds | No | 25 | D | |
| 33 | Grangeville | 1 compounds | No | 27 | B- | |
| 34 | Heyburn | 1 compounds | No | 28 | D | |
| 35 | Fort Hall | 1 compounds | No | 5 | D | |
| 36 | Potlatch | 1 compounds | No | 16 | B | |
| 37 | Kooskia | 1 compounds | No | 5 | A | |
| 38 | Coeur D Alene | 0 compounds | No | 125 | F | |
| 39 | Post Falls | 0 compounds | No | 56 | D | |
| 40 | Moscow | 0 compounds | No | 20 | C- | |
| 41 | Hayden | 0 compounds | No | 56 | D | |
| 42 | Sandpoint | 0 compounds | No | 328 | F | |
| 43 | Mountain Home | 0 compounds | No | 55 | D | |
| 44 | Preston | 0 compounds | No | 82 | F | |
| 45 | Hailey | 0 compounds | No | 7 | C | |
| 46 | Fruitland | 0 compounds | No | 120 | D | |
| 47 | Kellogg | 0 compounds | No | 90 | C+ | |
| 48 | Coeur D'Alene | 0 compounds | No | 87 | D | |
| 49 | Mccall | 0 compounds | No | 19 | F | |
| 50 | Sun Valley | 0 compounds | No | 13 | D | |
| 51 | Gooding | 0 compounds | No | 13 | B+ |
Frequently asked questions about pfas in Idaho
Does Idaho tap water contain PFAS?
PFAS were detected in 37 of 51 Idaho cities tested under EPA's UCMR 5 program. 3 cities exceed the 2024 EPA MCL of 4 ppt for individual PFAS compounds.
How can I remove PFAS from my drinking water in Idaho?
Reverse osmosis (RO) systems are the most effective at removing PFAS, typically removing 90%+ of compounds. High-quality activated carbon block filters (NSF 58-certified for RO, or NSF 53 for solid carbon) also provide significant reduction. Standard pitcher filters vary widely in PFAS removal.