PFAS Testing Results
Idaho
PFAS testing results for 61 water systems serving 1,329,500 residents.
3 systems exceed federal PFAS limits, affecting 168,840 residents.
Systems tested
61
13.1% had PFAS detections
Limits exceeded
3
4.9% of systems
Population affected
169K
served by systems over federal limits
Most common compound
11Cl-PF3OUdS
detected in 8 systems
Grade distribution
Every water system gets a letter grade based on how its worst detected PFAS compound compares to the federal Maximum Contaminant Level. Lower grades mean higher contamination.
Communities exceeding federal limits
The water systems in Idaho where at least one PFAS compound exceeds the EPA Maximum Contaminant Level, sorted worst first.
| System name | City | Grade | Worst compound | Times over limit | Population |
|---|---|---|---|---|---|
| GARDEN CITY WATER AND SEWER SYSTEM | GARDEN CITY | F | PFOS | 6.4x | 13K |
| CAPITOL WATER CORP | BOISE | D | PFNA | 2.2x | 9.0K |
| MERIDIAN WATER DEPT | MERIDIAN | D | PFOS | 1.1x | 147K |
Resources for taking action are available in our community toolkit.
What Idaho is doing about PFAS
As of April 2026, Idaho has not adopted state-level PFAS drinking water standards beyond the federal EPA limits finalized in April 2024. The Idaho Department of Environmental Quality has tracked contamination near Mountain Home Air Force Base and has not published enforceable state MCLs.
Public water systems in Idaho are subject to the federal compliance timeline requiring initial monitoring by 2027 and treatment installation by 2029.
Based on Idaho Department of Environmental Quality publications.
All 61 tested water systems in Idaho
Sorted from lowest grade to highest. Click any system name for the full report. Filter by city or name with the search box below.
Showing 50 of 61 systems
| Grade | System name | City | Worst compound | vs. EPA limit | Population |
|---|---|---|---|---|---|
F | GARDEN CITY WATER AND SEWER SYSTEM | GARDEN CITY | PFOS | 6.4× the federal limit | 13K |
D | CAPITOL WATER CORP | BOISE | PFNA | 2.2× the federal limit | 9.0K |
D | MERIDIAN WATER DEPT | MERIDIAN | PFOS | 1.1× the federal limit | 147K |
C | MOUNTAIN HOME AIR FORCE BASE | MOUNTAIN HOME AFB | PFHxS | 74% of federal limit | 7.5K |
C | LEWISTON CITY OF | LEWISTON | PFBS | Below detection | 15K |
B | RATHDRUM CITY OF | RATHDRUM | PFPeA | Below detection | 10K |
B | PAYETTE CITY OF | PAYETTE | PFPeA | Below detection | 8.1K |
B | SHELLEY CITY OF | SHELLEY | PFBS | Below detection | 4.4K |
A | KANIKSU SHORES ESTATES | SANDPOINT | - | Below detection | 82 |
A | SANDPOINT PUBLIC WORKS DEPT | SANDPOINT | - | Below detection | 12K |
A | AVONDALE IRRIGATION DIST | HAYDEN | - | Below detection | 8.8K |
A | COEUR D ALENE CITY OF | COEUR D ALENE | - | Below detection | 54K |
A | EAST GREENACRES IRRIGATION DIST | POST FALLS | - | Below detection | 11K |
A | HAYDEN LAKE IRRIGATION DIST | HAYDEN | - | Below detection | 9.4K |
A | POST FALLS CITY OF | POST FALLS | - | Below detection | 20K |
A | ROSS POINT WATER DIST | POST FALLS | - | Below detection | 9.0K |
A | COUGAR BAY WATER ASSOCIATION | COEUR D'ALENE | - | Below detection | 200 |
A | CENTRAL SHOSHONE COUNTY WATER DIST | KELLOGG | - | Below detection | 6.1K |
A | PIERCE CITY OF | PIERCE | - | Below detection | 467 |
A | GRANGEVILLE WATER DEPT | GRANGEVILLE | - | Below detection | 3.2K |
A | KOOSKIA WATER DEPT | KOOSKIA | - | Below detection | 607 |
A | MOSCOW WATER DEPT | MOSCOW | - | Below detection | 26K |
A | POTLATCH CITY OF | POTLATCH | - | Below detection | 812 |
A | UNIVERSITY OF IDAHO | MOSCOW | - | Below detection | 8.6K |
A | LEWISTON ORCHARDS IRRIGATION DIST | LEWISTON | - | Below detection | 20K |
A | CALDWELL CITY OF | CALDWELL | - | Below detection | 74K |
A | MIDDLETON CITY OF | MIDDLETON | - | Below detection | 13K |
A | NAMPA CITY OF | NAMPA | - | Below detection | 100K |
A | EMMETT CITY OF | EMMETT | - | Below detection | 6.7K |
A | FRUITLAND CITY OF | FRUITLAND | - | Below detection | 7.1K |
A | WEISER CITY OF | WEISER | - | Below detection | 5.6K |
A | Veolia Water ID | BOISE | - | Below detection | 265K |
A | Veolia Eagle | BOISE | - | Below detection | 11K |
A | KUNA CITY OF | KUNA | - | Below detection | 32K |
A | EAGLE, CITY OF (EASTERN ZONE) | EAGLE | - | Below detection | 3.7K |
A | STAR SEWER AND WATER DIST WATER SYSTEM | STAR | - | Below detection | 14K |
A | EAGLE, CITY OF (WESTERN ZONE) | EAGLE | - | Below detection | 6.1K |
A | MOUNTAIN HOME CITY OF | MOUNTAIN HOME | - | Below detection | 15K |
A | MCCALL CITY OF | MCCALL | - | Below detection | 4.4K |
A | HAILEY WATER AND SEWER | HAILEY | - | Below detection | 8.0K |
A | KETCHUM CITY OF | KETCHUM | - | Below detection | 3.6K |
A | SUN VALLEY WATER AND SEWER DIST | SUN VALLEY | - | Below detection | 3.4K |
A | BURLEY WATER DEPT | BURLEY | - | Below detection | 10K |
A | GOODING CITY OF | GOODING | - | Below detection | 3.7K |
A | JEROME CITY OF | JEROME | - | Below detection | 13K |
A | HEYBURN CITY OF | HEYBURN | - | Below detection | 3.0K |
A | RUPERT CITY OF | RUPERT | - | Below detection | 5.8K |
A | BUHL CITY OF | BUHL | - | Below detection | 4.5K |
A | TWIN FALLS CITY OF | TWIN FALLS | - | Below detection | 56K |
A | CHUBBUCK CITY OF | CHUBBUCK | - | Below detection | 16K |
Check your water system
Enter your zip code to see the PFAS results for the water system that serves your home.
Where this data comes from
- EPA Unregulated Contaminant Monitoring Rule, 5th cycle (UCMR 5)
- Testing period: 2023 to 2026
- Federal limits: EPA Maximum Contaminant Levels finalized April 2024
- Read the full methodology