Hard water in Lake Hiawatha, NJ
Reported by Parsippany-Troy Hills Water Department · May 2025
- NJ typical
- 80 mg/L
- EPA health violations since 2016
- 2
- Softener for 3 people
- 24k grain
- Data
- Utility report
The water in Lake Hiawatha carries roughly 208 mg/L of dissolved calcium and magnesium, or 12.2 grains per gallon. That is very hard water. The number comes from Parsippany-Troy Hills Water Department, dated May 2025.
At 208 mg/L, Lake Hiawatha is 128 mg/L above the typical New Jersey figure of 80. Of the 10 nearest cities we track, 7 have softer water and 1 has harder. The range nearby runs from 37 mg/L in Kinnelon to 269 in White Meadow Lake.
What 208 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 208 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 × 12.2 gpg = 2,736 grains a day. A 24,000-grain unit regenerates about every 8 days.
EPA record for Lake Hiawatha's water system
2 health-based violations since 2016
Serves about 50,400 people from surface water.
- Health-based
- 2
- Monitoring or reporting
- 48
- Open now
- 0
TapWaterData ties Lake Hiawatha to this system. EPA's service-area records do not name Lake Hiawatha, so check the utility printed on your water bill.
| Contaminant or rule | Violations | Period | Status |
|---|---|---|---|
| Lead and Copper Rulecorrosion control and lead sampling | 2 | 2019–2020 | Resolved |
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 Hiawatha water hard?
Yes. It measures about 208 mg/L (12.2 grains per gallon), which the USGS classes as very hard.
What is the water hardness in Lake Hiawatha in grains per gallon?
About 12.2 gpg. One grain per gallon equals 17.1 mg/L, so 208 mg/L divided by 17.1 gives 12.2.
What size water softener do I need in Lake Hiawatha?
For 3 people using 75 gallons each per day, 12.2 gpg works out to about 2,736 grains a day. A 24,000-grain softener covers that with a regeneration about every 8 days.
Has the Lake Hiawatha water system had EPA violations?
EPA records show 2 health-based violations for Parsippany-Troy Hills Water Department 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
- Parsippany208 mg/LVery hard
- Boonton92 mg/LModerately hard
- Pine Brook180 mg/LHard
- Troy Hills208 mg/LVery hard
- Towaco180 mg/LHard
- Whippany148 mg/LHard
- Morris Plains148 mg/LHard
- Kinnelon37 mg/LSoft
- Rockaway123 mg/LHard
- White Meadow Lake269 mg/LVery hard
Hardness data: TapWaterData US Water Hardness (utility report, May 19, 2025), CC BY 4.0. Population: US Census Bureau. Violations: EPA ECHO. How we use them.