Forever Chemicals
Maybe you are eyeing a move across the state, or just curious about the ground and water around a place you already call home. Either way, someone has actually pulled Montana's records into one view. The state's drinking-water oversight runs through the Montana Department of Environmental Quality (DEQ) and its public water supply program, so when a number below looks worrying, there is a named office behind it rather than a void. The figures and installations shown on this page are the public record for the state, not a verdict on any single tap. Think of this as a calm place to start when evaluating an address, and a way to understand what the records show before you go looking for more.
EPA's UCMR 5 program (2021–2024) tested 42 public water systems in Montana for 29 PFAS compounds; 1 reported at least one detection and none exceeded the 2024 federal limit of 4 ppt for PFOA/PFOS (a 2% detection rate). Detections vary by water system — check the utility serving a specific Montana address.
In Montana, the office that watches over drinking water is the Montana Department of Environmental Quality (DEQ), which runs the state's public water supply program and works through the federal Safe Drinking Water Act framework. On PFAS, Montana tends to sit among the states that lean on the federal limits the DEQ administers rather than setting its own enforceable drinking-water standard ahead of the April 2024 federal rule. That rule caps PFOA and PFOS at 4 parts per trillion, with limits on a few related compounds. The practical takeaway: a named state office is responsible here, and it is the DEQ that public water systems answer to.
Numbers below come straight from EPA UCMR 5 monitoring (2021–2024). Every public water system in Montanaserving more than 3,300 people had to test for 29 different PFAS — here's what they reported.
42
Water systems tested
UCMR 5 (2021–2024)
1
Systems with any PFAS detected
2% detection rate
0
Systems exceeding 2024 MCL
Above 4 ppt PFOA/PFOS
1
Distinct PFAS compounds detected
Of 29 monitored under UCMR 5
0
TRI-reporting PFAS facilities
EPA Toxics Release Inventory 2024
1
DoD PFAS installations
Military PFAS contamination sites
Red triangles are military installations the Department of Defense has flagged for PFAS from firefighting foam. Orange dots are industrial facilities that reported PFAS to the EPA Toxics Release Inventory. If your future home sits near a cluster, that's a conversation worth having with the seller or landlord.
These are the Montanautilities where EPA testing found PFAS the most often or at the highest levels. Being on this list doesn't automatically mean today's tap water is unsafe — some systems have added treatment since these samples were taken — but it means a conversation with the utility is worth having before you move in.
| Water system | Detections | Max value (ng/L) | vs 2024 MCL |
|---|---|---|---|
| MALMSTROM AIR FORCE BASE | 1 | 0.01 | Below MCL |
PFAS isn't one chemical — it's a family of thousands. Here are the specific compounds EPA picked up most often across Montana water systems. PFOA and PFOS are the two with the strictest federal limits (4 parts per trillion).
For decades the military trained with AFFF firefighting foam loaded with PFAS. It soaked into soil and groundwater and, in many places, traveled miles. If you're house-hunting near any of these Montana installations, the address report will tell you exactly how close.
Great Falls International Airport
Air Force
Looking at a specific Montanacity? Each page below pulls the same federal data narrowed to that water system — useful whether you're relocating, buying, organizing your neighborhood around getting cleaner water, or just trying to find out what's in the tap and what's around you.
Start with what the testing below can and cannot tell you. The federal UCMR5 monitoring looked for 29 PFAS compounds in public systems serving more than 3,300 people, sampled between 2021 and 2024. That leaves real gaps: private wells and many small rural systems were never required to test, and a detection logged in 2022 is not automatically what comes out of a tap today. Montana has a lot of rural ground and private wells, so if your water comes from one, the DEQ's well-testing guidance is the better path than reading too much into a public-system figure. Read the numbers above as a screening snapshot, not a final word, and you will read them correctly.
Yes. EPA UCMR 5 monitoring (2021–2024) tested 42 public water systems in Montana; 1 had at least one PFAS detection. Detections vary by water system — check your specific serving utility.
Montana tends to fall among the states that rely on the federal PFAS drinking-water limits the Montana Department of Environmental Quality (DEQ) administers, rather than adopting its own separate enforceable standard ahead of the 2024 federal rule. Those federal limits cap PFOA and PFOS at 4 parts per trillion.
The Montana Department of Environmental Quality oversees public water systems through its public water supply program and works within the federal Safe Drinking Water Act. Its handling of PFAS largely tracks the federal limits, which set PFOA and PFOS at 4 parts per trillion and add limits for a few related compounds.
The Montana Department of Environmental Quality, or DEQ, is the state agency responsible for protecting Montana's air, land, and water, including oversight of public drinking-water systems. It is the state-side office that public water utilities report to.
Use VetMyAddress to see the PFAS detections reported for the public water system serving any Montana address, alongside nearby military bases and industrial PFAS sources. The data comes from EPA UCMR 5, EPA TRI, and the DoD PFAS installation report.
In April 2024 the EPA set the first enforceable federal limits for PFAS in drinking water: 4 parts per trillion for PFOA and PFOS, and 10 ppt each for PFHxS, PFNA, and HFPO-DA (GenX), plus a Hazard Index for certain mixtures. Public water systems must complete initial monitoring by 2027 and come into compliance after that.
No. The federal limits apply to public water systems. Private well owners are responsible for their own testing and treatment, which is especially worth doing near a known PFAS source like a military base or industrial site.
State numbers tell you the pattern. An address report tells you what's actually in the water at yourkitchen sink — the matched utility, the PFAS detections on file, and every military or industrial source nearby. Whether it's for your family, your neighbors, or peace of mind.
Data sources: EPA UCMR 5 bulk data · EPA TRI 2024 · DoD PFAS installation report