Hard water in Forest Lake, MN
County estimate from 1,460 water samples in Anoka County · July 2026
- MN typical
- 160 mg/L
- EPA health violations since 2016
- 0
- Softener for 3 people
- 24k grain
- Data
- County estimate
Water samples from around Forest Lake put hardness at about 200 mg/L (11.7 gpg), which would be very hard on the USGS scale. Treat this as a rough guide: it is the median of 1,460 samples taken across Anoka County, mostly wells and streams, not a test of Forest Lake's treated tap water.
Forest Lake sits 40 mg/L above the typical Minnesota figure of 160. Of the 10 nearest cities we track, 6 have softer water and 3 have harder. The range nearby runs from 39 mg/L in Lino Lakes to 249 in Lake Elmo.
What 200 mg/L means at home
Scale forms fast here. Kettles and coffee makers need regular descaling, and showerheads clog unless you clean them.
Tank water heaters collect mineral sediment that insulates the water from the burner, so flushing the tank matters more than usual.
Dishes and glass shower doors spot easily. Soap scum and a dull film on hair or laundry are common complaints.
Hardness is not a health problem, and EPA sets no limit for it. It is a matter of scale and soap.
What to do about it
At 200 mg/L most of the trouble is scale, and only a few things deal with it.
Ion-exchange water softener
The standard whole-house fix. It swaps calcium and magnesium for sodium or potassium and needs salt plus a drain. Size it with the calculator below.
Salt-free conditioner
No salt and no drain line. It changes how minerals form scale instead of removing them, so water still tests hard.
Reverse osmosis or carbon filter
Under-sink reverse osmosis removes minerals from drinking water only. Plain carbon filters improve taste but do not soften.
3 people × 75 gallons a day × 11.7 gpg = 2,632 grains a day. A 24,000-grain unit regenerates about every 9 days.
EPA record for Forest Lake's water system
No health-based violations since 2016
Serves about 11,800 people from groundwater.
- Health-based
- 0
- Monitoring or reporting
- 2
- Open now
- 0
EPA lists this system as serving Forest Lake.
Health-based means a contaminant above its legal limit or a missed treatment step. Monitoring and reporting violations are late or missing tests and notices. Source: EPA ECHO, 2026Q3 export, violations with periods starting 2016 or later. Full EPA record.
Questions
Is Forest Lake water hard?
Yes. It measures about 200 mg/L (11.7 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Forest Lake in grains per gallon?
About 11.7 gpg. One grain per gallon equals 17.1 mg/L, so 200 mg/L divided by 17.1 gives 11.7.
What size water softener do I need in Forest Lake?
For 3 people using 75 gallons each per day, 11.7 gpg works out to about 2,632 grains a day. A 24,000-grain softener covers that with a regeneration about every 9 days.
Has the Forest Lake water system had EPA violations?
EPA records show no health-based violations for Forest Lake since 2016. There were also 2 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Lino Lakes39 mg/LSoft
- Blaine191 mg/LVery hard
- Mahtomedi162 mg/LHard
- Shoreview192 mg/LVery hard
- Maplewood56 mg/LSoft
- North St. Paul56 mg/LSoft
- New Brighton230 mg/LVery hard
- Coon Rapids201 mg/LVery hard
- Andover200 mg/LVery hard
- Lake Elmo249 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (county estimate, July 4, 2026), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.