State
Montana: drinking water records
EPA lists 849 community water systems serving homes in Montana. 40 took part in EPA's national PFAS survey (UCMR 5), and 5 found at least one PFAS above the level laboratories can measure.
Data as of EPA UCMR 5 final release, August 2026 (file dated Aug 28, 2026) · EPA SDWIS 2026Q2 (file dated Jul 9, 2026). How we build these pages
PFAS in EPA’s final survey
5 of the 40 Montana systems in EPA’s national PFAS survey found at least one PFAS, and 0 had a PFOA or PFOS yearly average at or above EPA’s limit. See Montana’s PFAS results by system and compound.
Counties
- Beaverhead County 9 systems
- Big Horn County 5 systems
- Blaine County 6 systems
- Broadwater County 2 systems
- Carbon County 12 systems
- Carter County 1 systems
- Cascade County 47 systems
- Chouteau County 11 systems
- Custer County 4 systems
- Daniels County 2 systems
- Dawson County 10 systems
- Deer Lodge County 6 systems
- Fallon County 4 systems
- Fergus County 11 systems
- Flathead County 142 systems
- Gallatin County 64 systems
- Garfield County 1 systems
- Glacier County 12 systems
- Golden Valley County 2 systems
- Granite County 1 systems
- Hill County 9 systems
- Jefferson County 14 systems
- Judith Basin County 4 systems
- Lake County 25 systems
- Lewis and Clark County 56 systems
- Liberty County 8 systems
- Lincoln County 19 systems
- Madison County 12 systems
- McCone County 2 systems
- Meagher County 3 systems
- Mineral County 10 systems
- Missoula County 85 systems
- Musselshell County 4 systems
- Park County 18 systems
- Petroleum County 1 systems
- Phillips County 7 systems
- Pondera County 10 systems
- Powder River County 1 systems
- Powell County 2 systems
- Prairie County 0 systems
- Ravalli County 24 systems
- Richland County 5 systems
- Roosevelt County 4 systems
- Rosebud County 4 systems
- Sanders County 12 systems
- Sheridan County 5 systems
- Silver Bow County 3 systems
- Stillwater County 7 systems
- Sweet Grass County 3 systems
- Teton County 9 systems
- Toole County 15 systems
- Treasure County 1 systems
- Valley County 8 systems
- Wheatland County 7 systems
- Wibaux County 1 systems
- Yellowstone County 54 systems
ZIP reports
Sources
EPA UCMR 5 occurrence data, samples collected 2023-01-03 – 2026-06-17, final release, August 2026 (file dated Aug 28, 2026); EPA SDWIS via ECHO, 2026Q2 extract (file dated Jul 9, 2026); EPA service-area boundaries v3.0; Census 2020 ZCTAs. Database prepared 2026-09-03.
