Stillwater Water Hardness & Quality Report (2026)
Water Hardness
15.9 grains per gallon
Source
river
pH Level
8.5
neutral = 7.0
Lead
0.008 mg/L
✓ Below action level
TDS
707.5 mg/L
Est. Daily Cost
$0.73
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 Stillwater, your appliances are currently losing 36% efficiency due to mineral buildup.
| Appliance | In Stillwater | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 1.5 yrs | 8.5 yrs | -82% |
| Washing Machine | 3.5 yrs | 12 yrs | -71% |
| Water Heater | 5 yrs | 15 yrs | -67% |
Regional Water Comparison
How Stillwater compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Stillwater, Minnesota | 272 mg/L | 7.4 ppt | 🔴 Very Hard | river |
| Hudson, Wisconsin | 206 mg/L | 5.5 ppt | 🔴 Very Hard | groundwater |
| Oakdale, Minnesota | 181 mg/L | 5.3 ppt | 🔴 Very Hard | river |
| Woodbury, Minnesota | 220.5 mg/L | 6.2 ppt | 🔴 Very Hard | river |
| White Bear Lake, Minnesota | 162.5 mg/L | 4.9 ppt | 🟠 Hard | river |
National Benchmark
How Stillwater compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Stillwater | 272 mg/L | 🔴 High |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Stillwater's Water Unique?
Local geology and source profile
Stillwater, Minnesota, in Washington County — the Washington County seat on the St. Croix River adjacent to Woodbury and Bayport, the birthplace of Minnesota and the first city in the territory, a historic lumber and river city on the Minnesota-Wisconsin border — receives its municipal water from the Stillwater Water Division, drawing from the St. Croix River at the Stillwater water treatment plant.
The hard 272 mg/L hardness and high TDS of 707.5 mg/L reflect the St. Croix River watershed's Upper Midwest carbonate geology. The St. Croix River drains the Upper Wisconsin highlands — Precambrian crystalline rock (insoluble), the Cambrian Jordan and Mt. Simon Sandstone (calcareous cement), and the Ordovician Prairie du Chien Dolomite Group (thick dolomite platform). The dominant hardness contribution comes from the Prairie du Chien carbonate sequence, which outcrops extensively in the Wisconsin-Minnesota border region and contributes calcium and magnesium to the St. Croix supply, producing the hard water characteristic of the Stillwater-St. Croix corridor.
At 272 mg/L with TDS 708 mg/L, Stillwater's water is hard. A water softener is strongly recommended. Scale builds rapidly in appliances and plumbing. The PFAS level of 7.4 ppt warrants a certified drinking water filter — the Twin Cities metro industrial corridor (Washington County-Ramsey County), the 3M Cottage Grove complex (Washington County — a major documented PFAS manufacturer with PFAS contamination in the St. Croix-Mississippi watershed), and the upper Midwest PFAS legacy contribute to Stillwater's elevated readings.
Geology & Source: Stillwater in Washington County draws from the St. Croix River (Washington County, MN-WI border) via the Stillwater Water Division — the St. Croix drains the Upper Midwest (calcareous Pleistocene till over Ordovician Prairie du Chien Dolomite and Cambrian Jordan Sandstone) — Minnesota-Wisconsin St. Croix Ordovician dolomite drainage produces hard water at 272 mg/L with high TDS 708 mg/L in this Washington County Minnesota city.