Water hardness in Forest Lake
6 gpg moderately hard
Tap water in Forest Lake is moderately hard: 6 gpg (103 mg/L · 5.8 °dH · 10.3 °fH).
Source: City of Forest Lake – Water Department page (2025) · data checked 2026-11-02
Range across supply zones: 94–111 mg/L.
The Forest Lake Water Department publishes values that give a computed hardness of 102.7 mg/L, with a range of 94.2 to 111.3 mg/L. That is moderate hardness, and the spread is narrow. Light scale on fixtures is typical at this level.
USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
Water data
| Total hardness | 6 gpg |
|---|---|
| Utility | City of Forest Lake Water Department |
How Forest Lake compares
- Tap water in Forest Lake is 34 % softer than the median of the 1372 cities we track in the United States (9.1 gpg).
- By hardness it ranks 1002 of 1372 in the United States (1 = hardest); 27 % of these cities have softer water.
- In Minnesota it is number 18 of 23 cities; the regional median is 17 gpg.
Ranking of the hardest and softest water in the United States →
What it means at home
- Visible kettle scale every few weeks; vinegar or citric acid is enough.
- Water heater and washing machine: some long-term scale; a scale inhibitor slows it.
- Dishwasher: medium salt setting.
- Softener optional; pays off mainly with a gas boiler or tankless heater.
How much salt will you use for softening?
Optional. A scale inhibitor or a small softener protects the heater; soap savings are modest.
Descale a coffee machine or kettle about every 3 months (typical manufacturer guidance for this hardness).
Estimates for planning, not a quote. Check your appliance manual for exact settings.
Dishwasher setting in Forest Lake
| Brand | Setting for this water |
|---|---|
| Bosch | H00 |
| Miele | 6 °dH |
| AEG / Electrolux | 2 |
| Beko | 2nd |
| Hoover | S1 |
| LG | H1 |
From each brand's manual for the model family named in the source; your model may differ, so check its manual. All brands and how to change the setting →
FAQ
Is Forest Lake water hard or soft?
It is moderately hard: 103 mg/L as CaCO₃ (6 gpg, 5.8 °dH). The usual bands are soft < 60, moderately hard 60–120, hard 120–180 and very hard > 180 mg/L.
Is tap water in Forest Lake safe to drink?
Hardness is not a health issue; it is about limescale, taste and appliances. Mains water must meet national drinking-water standards. USGS classes: soft 0–60, moderately hard 61–120, hard 121–180, very hard >180 mg/L.
How many grains per gallon is Forest Lake water?
6 gpg, equal to 5.8 °dH, 10.3 °fH or 103 mg/L calcium carbonate.
What dishwasher salt setting should I use in Forest Lake?
For 103 mg/L (5.8 °dH) check your manufacturer's table: level 2–3.
Do I need a water softener in Forest Lake?
Not essential; a scale inhibitor protects the heater cheaply.
Source
Source: City of Forest Lake – Water Department page (2025). Method: computed from supplier's calcium and magnesium. City of Forest Lake – Water Department page · Outdated figure? Tell us