Great Falls Water Hardness & Quality Report (2026)
Water Hardness
9.6 grains per gallon
Source
reservoir
pH Level
8.2
neutral = 7.0
Lead
0.009 mg/L
✓ Below action level
TDS
432.2 mg/L
Est. Daily Cost
$0.44
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
0–60
mg/L
Soft
61–120
mg/L
Moderately Hard
121–180
mg/L
Hard
180+
mg/L
Very Hard
Appliance Damage Report
In Great Falls, your appliances are currently losing 22% efficiency due to mineral buildup.
| Appliance | In Great Falls | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 4.2 yrs | 8.5 yrs | -51% |
| Washing Machine | 7.5 yrs | 12 yrs | -38% |
| Water Heater | 9 yrs | 15 yrs | -40% |
Regional Water Comparison
How Great Falls compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Great Falls, Montana | 164.5 mg/L | 2.9 ppt | 🟠 Hard | reservoir |
| Helena, Montana | 113 mg/L | 2.2 ppt | 🟡 Moderately Hard | reservoir |
| Bozeman, Montana | 132 mg/L | 2.5 ppt | 🟠 Hard | reservoir |
| Butte, Montana | 56 mg/L | 1.4 ppt | 🟢 Soft | reservoir |
| Missoula, Montana | 80.5 mg/L | 1.8 ppt | 🟡 Moderately Hard | reservoir |
National Benchmark
How Great Falls compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Great Falls | 164.5 mg/L | 🟠 Moderate |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Great Falls's Water Unique?
Local geology and source profile
Great Falls, Montana, the Cascade County seat on the Missouri River at the confluence with the Sun River — the 'Electric City' built around the Great Falls of the Missouri River (the famous waterfalls Lewis and Clark took weeks to portage), now a major regional hub in north-central Montana — draws its municipal water supply from the Missouri River via the City of Great Falls Water Treatment Plant, treating Missouri River water for the Great Falls area. Water hardness in Great Falls measures 164.5 mg/L — classified as hard.
Great Falls' hard supply reflects the Missouri River's Rocky Mountain Front Range calcareous geology. The Missouri River above Great Falls (the upper Missouri headwaters system) drains: the Lewis and Clark Range and Rocky Mountain Front (Belt Supergroup Precambrian Siyeh Formation limestone and Grinnell Argillite — the extraordinarily thick Precambrian calcareous Purcell–Belt sedimentary sequence of the Rocky Mountain Front); the Cretaceous Two Medicine Formation and Virgelle Sandstone (calcareous Cretaceous marine formations of the Sweetgrass Arch area); and the Rocky Mountain thrust belt overthrust carbonates. The Belt Supergroup Siyeh Limestone is one of the most reactive calcareous Precambrian sequences in North America, contributing substantial dissolved calcium to the upper Missouri.
At 164.5 mg/L, Great Falls residents face regular hard water challenges. Scale deposits form on faucet aerators, showerheads, and appliances within weeks — monthly descaling with citric acid solution is standard maintenance. City of Great Falls Water Treatment Plant consistently delivers water meeting all Montana DEQ and EPA Safe Drinking Water Act requirements.
Geology & Source: River supply from the Missouri River via the City of Great Falls Water Treatment Plant — the Missouri River Rocky Mountain Front Range (Belt Supergroup Precambrian calcareous metasediments, Cretaceous Two Medicine Formation, and Rocky Mountain Front overthrust belt) drainage of Cascade County; hard supply at 164.5 mg/L in Cascade County, Montana.