SWEETGRASS WATER USERS ASSN
SWEET GRASS, MT · 100 people served · EPA PWSID MT0000340
SWEETGRASS WATER USERS ASSN (SWEET GRASS, MT), which serves about 100 people, has recorded 1 health-based drinking-water contaminant in EPA violation records since 2016, most notably Total Trihalomethanes (TTHM). Its most recent lead 90th-percentile sample was 15.0 ppb, above the 15 ppb federal action level. A certified water filter can reduce these at the tap — see the certified options for each below.
What the testing found
Measured levels from EPA violation records, compared to the federal limit (MCL). The black line marks the legal limit.
Lead
1× the federal limitNo safe level. Damages developing brain/nervous system in children; linked to lower IQ, kidney and cardiovascular harm in adults. Usually enters water from corroding pipes/solder, not the source.
Copper
1.15× the federal limitShort-term: nausea/vomiting/cramps; long-term: liver/kidney damage. Leaches from copper plumbing, worse with corrosive water.
Total Trihalomethanes
1× the federal limitChlorination byproduct; MCL 80 ug/L. Long-term bladder cancer and reproductive risk. Higher in surface-water systems.
Filters certified to clean up your water
Your water shows Lead, Copper, Total Trihalomethanes. A reverse osmosis system handles the most of this in one unit — these three are independently certified for the most of your contaminants (not marketing claims):
Compare all certified reverse osmosis filters →
Want certainty about your tap specifically (not just the system)? A certified mail-in lab test is the gold standard — system-wide records can differ from your home's plumbing. Some links above are affiliate links — see our disclosure.
Sources & method. Contaminant levels and violations come from EPA's Safe Drinking Water Information System (health-based violations, 2016–present); PFAS from EPA UCMR5 monitoring (2023–2025). Levels shown are the highest recorded value in the violation records; a violation means the contaminant exceeded its federal limit at the system level. Your home's water can differ from the system average. Public domain data; we are not affiliated with the EPA.