Hard water in Lake Mohawk, NJ
Reported by Sparta TWP Water Utility - Lake Mohawk · September 2025
- NJ typical
- 80 mg/L
- EPA health violations since 2016
- 4
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Lake Mohawk carries roughly 158 mg/L of dissolved calcium and magnesium, or 9.2 grains per gallon. That is hard water. The number comes from Sparta TWP Water Utility - Lake Mohawk, dated September 2025.
Lake Mohawk sits 78 mg/L above the typical New Jersey figure of 80. Of the 10 nearest cities we track, 7 have softer water and 3 have harder. The range nearby runs from 37 mg/L in Kinnelon to 269 in White Meadow Lake.
What 158 mg/L means at home
Expect white crust on faucets and showerheads, plus spots on dishes that come out of the dishwasher.
Kettles collect scale quickly. Water heaters build up sediment at the bottom of the tank, which makes them work harder over time.
Soap and detergent need a little more to lather, and soap scum shows up in the tub.
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 158 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 × 9.2 gpg = 2,079 grains a day. A 24,000-grain unit regenerates about every 11 days.
EPA record for Lake Mohawk's water system
4 health-based violations since 2016
Serves about 17,625 people from groundwater.
- Health-based
- 4
- Monitoring or reporting
- 48
- Open now
- 2
TapWaterData ties Lake Mohawk to this system. EPA's service-area records do not name Lake Mohawk, so check the utility printed on your water bill.
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Lead and Copper Rulecorrosion control and lead sampling | 4 | 2020–2023 | 1 open |
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 Lake Mohawk water hard?
Yes. It measures about 158 mg/L (9.2 grains per gallon), which the USGS classes as hard.
What is the water hardness in Lake Mohawk in grains per gallon?
About 9.2 gpg. One grain per gallon equals 17.1 mg/L, so 158 mg/L divided by 17.1 gives 9.2.
What size water softener do I need in Lake Mohawk?
For 3 people using 75 gallons each per day, 9.2 gpg works out to about 2,079 grains a day. A 24,000-grain softener covers that with a regeneration about every 11 days.
Has the Lake Mohawk water system had EPA violations?
EPA records show 4 health-based violations for Sparta TWP Water Utility - Lake Mohawk since 2016, involving Lead and Copper Rule. There were also 48 monitoring or reporting violations, which are about late or missing tests and notices.
Nearby cities
- Wharton43 mg/LSoft
- White Meadow Lake269 mg/LVery hard
- Rockaway123 mg/LHard
- Kinnelon37 mg/LSoft
- Boonton92 mg/LModerately hard
- Morris Plains148 mg/LHard
- Butler37 mg/LSoft
- Parsippany208 mg/LVery hard
- Lake Hiawatha208 mg/LVery hard
- Morristown148 mg/LHard
Hardness data: TapWaterData US Water Hardness (utility report, September 22, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.