Is Dillon, MT tap water safe?
The short answer
3 of the 7 utilities serving Dillon have a result above a legal limit or action level, or a health-based violation since 2016, in EPA’s and Montana’s records: Hildreth Subdivision No 3, Skyline Tr CT and Rv Park and Clarks Lookout.
City of Dillon, which serves the most people here, has 3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 21 ppb, above EPA’s health benchmark. Health goals are stricter than legal limits and are not enforced.
A town can be served by more than one utility, and some homes are on private wells. The name on your water bill tells you which is yours, and your ZIP code narrows it down. They are listed by how many people each serves in Dillon’s ZIP codes, from EPA’s estimates.
- Open report
City of Dillon
Montana · serves 4,300 people · under 100 in Dillon
3 results above the health goal and 1 result above EPA’s health benchmark. The worst: Lithium at 21 ppb, above EPA’s health benchmark.
No health-based violations since 2016
- Open report
Keller Subdivision No 2 HOA
Montana · serves 300 people · lists Dillon among the places it serves
3 results above the health goal. The worst: Arsenic at 3.0 ppb, above the health goal.
No health-based violations since 2016
- Open report
Hildreth Subdivision No 2
Montana · serves 300 people · lists Dillon among the places it serves
3 results above the health goal. The worst: Arsenic at 3.0 ppb, above the health goal.
No health-based violations since 2016
- Open report
Hildreth Subdivision No 3
Montana · serves 128 people · lists Dillon among the places it serves
2 results above the health goal. The worst: Arsenic at 3.0 ppb, above the health goal.
1 health-based violation since 2016
- Open report
Western Mobile Village Dillon
Montana · serves 75 people · lists Dillon among the places it serves
3 results above the health goal. The worst: Arsenic at 6.5 ppb, above the health goal.
No health-based violations since 2016
- Open report
Skyline Tr CT and Rv Park
Montana · serves 75 people · lists Dillon among the places it serves
3 results above the health goal. The worst: Arsenic at 8.0 ppb, above the health goal.
2 health-based violations since 2016
- Open report
Clarks Lookout
Montana · serves 62 people · lists Dillon among the places it serves
2 results above the health goal. The worst: Arsenic at 3.8 ppb, above the health goal. Hardness: soft to hard depending on the source, 60 to 157 mg/L (3.5 to 9.2 grains per gallon).
16 health-based violations since 2016
What handles it
Each of these is certified, on a certifier’s listing, for a result above a line in City of Dillon’s water, which serves the most people here. Another utility’s report names what handles its own results.
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Countertop reverse osmosis
- IAPMO listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 4, 2026
Certified for: Arsenic, Lead
Aquasana SmartFlow Reverse Osmosis (AQ-SFRO2)
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic, Lead
Brondell Capella RC250 Reverse Osmosis System
Under-sink reverse osmosis
- WQA listing:NSF/ANSI 42NSF/ANSI 53NSF/ANSI 58NSF/ANSI 401checked Oct. 9, 2026
Certified for: Arsenic, Lead
Water testing near Dillon
The 2 labs Montana certifies closest to Dillon, in a straight line. Call first: certification is test by test, and not every lab takes samples from homeowners.
Montana Bureau of Mines and Geology
Butte, MT · about 67 miles
Certified for minerals and other inorganics
MSM Laboratory
Butte, MT · about 67 miles
Certified for bacteria
Montana State Environmental Laboratory: Private well testing packages for bacteria, metals, nutrients, anions, organic chemicals and more, open to the public. Samples can be mailed, sent by the lab's free courier, or dropped off at the lab. Environmental Laboratory, Montana Department of Public Health and Human Services.
All 36 certified labs for MontanaZIP codes in Dillon
Which ZIP codes are in Dillon: Census 2020 relationship files. Which utilities serve them, and how many people: EPA SDWIS and EPA’s service area map. Each utility’s results: EPA UCMR 5, EPA SDWIS, and EPA’s and the state’s compliance monitoring, as its report lists them. How they are measured: methodology. Certified labs: Montana Department of Public Health and Human Services, Water Laboratory Certification Program, certified laboratories; distances from the Census 2020 ZIP code tabulation area gazetteer.
What to do next
- Read City of Dillon’s full reportEvery result with its dates, the violations, and the certification claim that handles each finding.Open the report
- About LithiumWhat it does to health, where it comes from, and the certification claim that addresses it.About Lithium
- On a private well?No utility tests a well. A certified lab test is the first step.How to test well water