Great Falls City Of, MT
Above the new 10 ppb level coming in 2027
Latest 90th-percentile lead: 12 ppb (monitoring period 2026-2026). The federal action level is 15 ppb today and drops to 10 ppb in Nov 2027; EPA's health goal is 0. Under the current 15 ppb rule this is not an exceedance, but it is above the 10 ppb action level that takes over in Nov 2027. Test your own tap; filter if your result shows lead.
Great Falls City Of at a glance
Great Falls City Of serves about 60,000 people through 22,477 service connections, which makes it a large system under EPA's size classes. It is owned by a local government (city, town, county or district) and draws surface water, in Cascade County, Montana. EPA system ID: MT0000525; phone on file: 406-727-1325. Ask them for your address in their service line inventory - every system had to publish one by Oct 2024.
Every lead result on file
That is up 4 ppb from 8 ppb in the period ending 2025. The highest 90th-percentile result EPA holds for Great Falls City Of is 12 ppb across 10 monitoring periods, none of them over 15 ppb (1 over 10 ppb).
| Period ending | 90th-percentile lead |
|---|---|
| 2026 | 12 ppb over 10 |
| 2025 | 8 ppb |
| 2025 | 7 ppb |
| 2024 | 8 ppb |
| 2024 | 9 ppb |
| 2024 | 9 ppb |
| 2023 | 10 ppb |
| 2020 | 3 ppb |
| 2019 | 4 ppb |
| 2016 | 5 ppb |
Against other Montana systems
Of the 753 Montana systems with a lead result, the median latest reading is 1 ppb; 5 are over 15 ppb right now and 28 have gone over at some point. Great Falls City Of's 12 ppb sits at the 99th percentile in Montana and the 98th nationally (higher means more lead).
Neighbouring systems
41 other systems share Cascade County; 0 of them have a higher latest lead result than Great Falls City Of. If you are unsure which one supplies your house, the name on your water bill decides it.
| System | People | Latest lead |
|---|---|---|
| Malmstrom Air Force Base | 8,850 | 0 (not detected) |
| Sun Prairie Village County | 1,800 | 1 ppb |
| Black Eagle Cascade County Water Sewer | 1,233 | 0 (not detected) |
| Prairie Water Company | 1,000 | 0 (not detected) |
| Cascade Town Of | 650 | 2 ppb |
| Belt Town Of | 600 | 0 (not detected) |
| Vaughn Cascade County Water And Sewer | 585 | 0 (not detected) |
| Two Buttes Water Users Assn | 525 | 2 ppb |
| Gore Hill County Water Dist | 500 | 1 ppb |
| Homestead Acres County Water And Sewer | 500 | 0 (not detected) |
Next steps for Great Falls, MT
Test your own tap with a certified lab first-draw sample; Great Falls, MT may offer free or low-cost kits through the utility. If your own line is lead, replacing the private side runs about $1,200-$12,300 (EPA average about $4,700). Ask Great Falls City Of whether it covers that cost before hiring anyone - many utilities now do.
These figures describe homes the utility sampled, not your tap. Only your service line record or a test of your own water answers the question for your house. The lead result guide covers how utilities pick the homes they sample. See what changes at 10 ppb in 2027.