All 54 systems had enough required samples to calculate a yearly average. 2 had at least one yearly average at or above a study benchmark; 52 did not.
EPA-based study benchmark: the unrounded cutoff this research uses to reproduce EPA’s January 2026 technical-assistance classification around the April 2024 federal levels. It is not a current standard or compliance finding and cannot determine household exposure or health risk.
Find your water system
ZIP codes are used only to route visitors to public water systems that reported serving them. Confirm the actual provider using a water bill or utility record.
System counts in Idaho
Each count shows how many included water systems had a yearly average at or above the named study benchmark.
| Study benchmark | Systems at or above benchmark | Water systems included | Percent |
|---|---|---|---|
| PFOA: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 1 | 54 | 1.9% |
| PFOS: 4.05 ppt study benchmark (reproduces EPA classification around 4 ppt) | 2 | 54 | 3.7% |
| PFHxS: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 1 | 54 | 1.9% |
| PFNA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 1 | 54 | 1.9% |
| HFPO-DA: 15 ppt study benchmark (reproduces EPA classification around 10 ppt) | 0 | 54 | 0.0% |
| Hazard Index: 1.5 study benchmark with at least two detected components (reproduces EPA classification around 1) | 2 | 54 | 3.7% |
Community water systems with complete monitoring
“Complete monitoring” means at least one sampling location had all required samples needed for a yearly average. Each PWSID appears once, preventing double counting across ZIP associations.
| Public water system | PWSID | Population served | Primary source | Sampling locations | Study benchmark result |
|---|---|---|---|---|---|
| AMERICAN FALLS CITY OF | ID6390001 | 4,863 | Ground water | 6 | Below all study benchmarks |
| AMMON CITY OF | ID7100004 | 17,338 | Ground water | 4 | Below all study benchmarks |
| AVONDALE IRRIGATION DIST | ID1280008 | 8,785 | Ground water | 4 | Below all study benchmarks |
| BLACKFOOT CITY OF | ID6060007 | 13,224 | Ground water | 7 | Below all study benchmarks |
| BUHL CITY OF | ID5420007 | 4,518 | Ground water | 5 | Below all study benchmarks |
| BURLEY WATER DEPT | ID5160008 | 10,345 | Ground water | 5 | Below all study benchmarks |
| CALDWELL CITY OF | ID3140013 | 74,000 | Ground water | 15 | Below all study benchmarks |
| CAPITOL WATER CORP | ID4010022 | 9,000 | Ground water | 4 | At or above a study benchmark |
| CHUBBUCK CITY OF | ID6030008 | 15,842 | Ground water | 5 | Below all study benchmarks |
| COEUR D ALENE CITY OF | ID1280053 | 54,115 | Ground water | 11 | Below all study benchmarks |
| COUGAR BAY WATER ASSOCIATION | ID1280309 | 230 | Ground water | 2 | Below all study benchmarks |
| EAGLE, CITY OF (EASTERN ZONE) | ID4010201 | 3,702 | Ground water | 2 | Below all study benchmarks |
| EAGLE, CITY OF (WESTERN ZONE) | ID4010222 | 6,108 | Ground water | 3 | Below all study benchmarks |
| EAST GREENACRES IRRIGATION DIST | ID1280064 | 11,165 | Ground water | 3 | Below all study benchmarks |
| FALLS WATER COMPANY INC | ID7100030 | 22,650 | Ground water | 7 | Below all study benchmarks |
| FRUITLAND CITY OF | ID3380005 | 7,458 | Surface water | 1 | Below all study benchmarks |
| GARDEN CITY WATER AND SEWER SYSTEM | ID4010066 | 12,500 | Ground water | 8 | At or above a study benchmark |
| GRANGEVILLE WATER DEPT | ID2250023 | 3,151 | Ground water | 5 | Below all study benchmarks |
| HAILEY WATER AND SEWER | ID5070022 | 8,000 | Ground water | 5 | Below all study benchmarks |
| HAYDEN LAKE IRRIGATION DIST | ID1280087 | 9,375 | Ground water | 6 | Below all study benchmarks |
| HEYBURN CITY OF | ID5340006 | 3,000 | Ground water | 3 | Below all study benchmarks |
| IDAHO FALLS CITY OF | ID7100039 | 69,450 | Ground water | 15 | Below all study benchmarks |
| KANIKSU SHORES ESTATES | ID1090065 | 93 | Ground water | 1 | Below all study benchmarks |
| KETCHUM CITY OF | ID5070028 | 3,555 | Ground water | 6 | Below all study benchmarks |
| KOOSKIA WATER DEPT | ID2250032 | 607 | Ground water | 2 | Below all study benchmarks |
| KUNA CITY OF | ID4010085 | 32,038 | Ground water | 5 | Below all study benchmarks |
| LEWISTON CITY OF | ID2350014 | 15,001 | Surface water | 6 | Below all study benchmarks |
| LEWISTON ORCHARDS IRRIGATION DIST | ID2350015 | 20,000 | Ground water | 2 | Below all study benchmarks |
| MCCALL CITY OF | ID4430033 | 4,423 | Surface water | 1 | Below all study benchmarks |
| MERIDIAN WATER DEPT | ID4010097 | 147,340 | Ground water | 24 | Below all study benchmarks |
| MIDDLETON CITY OF | ID3140074 | 13,190 | Ground water | 7 | Below all study benchmarks |
| MORELAND COUNTRY COURT | ID6060049 | 60 | Ground water | 2 | Below all study benchmarks |
| MOSCOW WATER DEPT | ID2290023 | 26,000 | Ground water | 5 | Below all study benchmarks |
| MOUNTAIN HOME AIR FORCE BASE | ID4200054 | 7,500 | Ground water | 3 | Below all study benchmarks |
| MOUNTAIN HOME CITY OF | ID4200032 | 14,651 | Ground water | 9 | Below all study benchmarks |
| NAMPA CITY OF | ID3140080 | 100,200 | Ground water | 13 | Below all study benchmarks |
| PAYETTE CITY OF | ID3380009 | 8,127 | Ground water | 7 | Below all study benchmarks |
| PIERCE CITY OF | ID2180027 | 467 | Surface water | 1 | Below all study benchmarks |
| POCATELLO CITY OF | ID6030043 | 58,231 | Ground water | 6 | Below all study benchmarks |
| POST FALLS CITY OF | ID1280147 | 20,285 | Ground water | 9 | Below all study benchmarks |
| POTLATCH CITY OF | ID2290030 | 812 | Ground water | 3 | Below all study benchmarks |
| PRESTON CITY OF | ID6210014 | 5,591 | Ground water | 1 | Below all study benchmarks |
| RATHDRUM CITY OF | ID1280152 | 10,358 | Ground water | 5 | Below all study benchmarks |
| REXBURG CITY OF | ID7330022 | 40,695 | Ground water | 4 | Below all study benchmarks |
| RIGBY CITY OF | ID7260032 | 5,400 | Ground water | 5 | Below all study benchmarks |
| ROSS POINT WATER DIST | ID1280163 | 8,965 | Ground water | 5 | Below all study benchmarks |
| RUPERT CITY OF | ID5340017 | 5,796 | Ground water | 3 | Below all study benchmarks |
| SANDPOINT PUBLIC WORKS DEPT | ID1090121 | 12,284 | Surface water | 2 | Below all study benchmarks |
| SHELLEY CITY OF | ID6060071 | 4,409 | Ground water | 4 | Below all study benchmarks |
| ST ANTHONY | ID7220067 | 3,606 | Ground water | 2 | Below all study benchmarks |
| STAR SEWER AND WATER DIST WATER SYSTEM | ID4010220 | 14,000 | Ground water | 4 | Below all study benchmarks |
| UNIVERSITY OF IDAHO | ID2290042 | 8,589 | Ground water | 2 | Below all study benchmarks |
| Veolia Water ID | ID4010016 | 264,978 | Surface water | 10 | Below all study benchmarks |
| WEISER CITY OF | ID3440011 | 5,630 | Surface water | 1 | Below all study benchmarks |
What is included
Each active community water system with enough required samples for a yearly average is counted once, even if it is linked with several ZIP codes. This does not mean every home was tested. Private wells are excluded, and UCMR 5 did not comprehensively monitor every small system. This page does not apply Idaho's state-specific standards or determine compliance. Use the official state or territory drinking-water program for current regulatory information.