Forest Lake Water Hardness & Quality Report (2026)
Water Hardness
10.7 grains per gallon
Source
river
pH Level
8.1
neutral = 7.0
Lead
0.005 mg/L
✓ Below action level
TDS
388.4 mg/L
Est. Daily Cost
$0.49
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 Forest Lake, your appliances are currently losing 25% efficiency due to mineral buildup.
| Appliance | In Forest Lake | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 3.5 yrs | 8.5 yrs | -59% |
| Washing Machine | 6.8 yrs | 12 yrs | -43% |
| Water Heater | 8.2 yrs | 15 yrs | -45% |
Regional Water Comparison
How Forest Lake compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Forest Lake, Minnesota | 184 mg/L | 5.4 ppt | 🔴 Very Hard | river |
| Hugo, Minnesota | 283 mg/L | 7.6 ppt | 🔴 Very Hard | river |
| Lino Lakes, Minnesota | 176.5 mg/L | 5.2 ppt | 🟠 Hard | river |
| White Bear Lake, Minnesota | 162.5 mg/L | 4.9 ppt | 🟠 Hard | river |
| Vadnais Heights, Minnesota | 255.5 mg/L | 7 ppt | 🔴 Very Hard | river |
National Benchmark
How Forest Lake compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Forest Lake | 184 mg/L | 🔴 High |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Forest Lake's Water Unique?
Local geology and source profile
Forest Lake, Minnesota, in Washington County — a Washington County city at the south end of Forest Lake in the northeastern Twin Cities exurban corridor, adjacent to the Chisago Lake area and Scandia in the Washington-Chisago County corridor — receives its municipal water from Forest Lake Public Utilities, which draws from the St. Croix River or local Washington County bedrock wells in the Prairie du Chien Dolomite aquifer system.
The moderately hard 184 mg/L hardness and TDS of 388.4 mg/L essentially match Willmar's readings (184 mg/L, TDS 388.1) — reflecting a common Minnesota aquifer supply type. Forest Lake either draws from the Ordovician Prairie du Chien Dolomite bedrock wells (the standard Washington County aquifer) or from a blend of St. Croix River and local groundwater. The Prairie du Chien Dolomite is the dominant bedrock aquifer throughout the Twin Cities eastern metro and St. Croix Valley, producing the consistently moderately hard water (160-200 mg/L) characteristic of Washington and Chisago Counties.
At 184 mg/L, Forest Lake's water is moderately hard — scale builds in kettles and appliances over months, dishwashers benefit from rinse aid, and bathroom fixtures develop calcium deposits. Quarterly descaling is appropriate. The PFAS level of 5.4 ppt warrants a certified drinking water filter — 3M's Minnesota PFAS manufacturing legacy (Cottage Grove, Washington County — a documented major PFAS source in the St. Croix watershed), the Washington County 3M corridor PFAS groundwater, and the Twin Cities eastern metro PFAS complex contribute to Forest Lake's readings.
Geology & Source: Forest Lake in Washington County draws from Forest Lake Public Utilities on the St. Croix River or the Prairie du Chien Dolomite bedrock aquifer (Washington County) — the St. Croix drains the Lake Superior Highlands (Precambrian Superior Upland crystalline) and the Minnesota calcareous till — Minnesota Prairie du Chien dolomite aquifer produces moderately hard water at 184 mg/L with TDS 388 mg/L in this Washington County Minnesota city.