How does Denville's water compare to the national average?

The USA national average is 151 mg/L. Denville (≈ 120–179 mg/L) is 1 mg/L softer than average.

Denville Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

groundwater

pH Level

7.4

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

124 mg/L

Est. Daily Cost

$0.40

energy & soap waste

Source: See methodology section below · Updated 2026

hard~120–179 mg/LHard · est.

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 Denville, your appliances are currently losing 20% efficiency due to mineral buildup.

Appliance	In Denville	Soft Water City	Efficiency Loss
Kettle	6.8 yrs	8.5 yrs	-20%
Washing Machine	9.6 yrs	12 yrs	-20%
Water Heater	12 yrs	15 yrs	-20%

Regional Water Comparison

How Denville compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Denville, New Jersey	≈ 120–179 mg/L	185.7 ppt	🟠 Hard	groundwater
Parsippany, New Jersey	≈ 180+ mg/L	548.5 ppt	🔴 Very Hard	reservoir
Dover, New Jersey	≈ 120–179 mg/L	123.5 ppt	🟠 Hard	groundwater
Morristown, New Jersey	≈ 120–179 mg/L	7.5 ppt	🟠 Hard	groundwater
Randolph, New Jersey	≈ 120–179 mg/L	0 ppt	🟠 Hard	groundwater

National Benchmark

How Denville compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Denville	≈ 120–179 mg/L	🟠 Moderate
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

Bring Scarsdale-quality water to your Denville home

Shop water softeners on Amazon.com →

Shop Now

What Makes Denville's Water Unique?

Local geology and source profile

Source: GroundwaterTDS: 124 mg/LpH: 7.4

The Denville Municipal Utilities Authority manages the water supply for Denville, New Jersey, which relies on regional groundwater or surface supplies common to northern New Jersey. The area's water sources include the Boonton Reservoir and the Rockaway River, although specific treatment plant names were not confirmed. As a resident of Denville, you'll get your water from the New Jersey American Water company, which draws from the Boonton Reservoir.

The underlying geology in Denville includes Triassic-age sandstones, shales, and conglomerates of the Newark Basin, along with some Precambrian Highlands bedrock. These formations contribute to a moderately mineralised supply due to natural dissolution of minerals. The area's hard supply character stems from limestone and dolomite influences in adjacent regions, though specific aquifer details like the Passaic Formation were not detailed.

If you live in Denville, you might notice that your appliances, like water heaters, dishwashers, and washing machines, don't last as long as they should due to moderate scale buildup. To extend their life and improve cleaning results, consider regular maintenance like vinegar descaling and installing a water softener. Since Denville's water is moderately hard, it's a good idea to take these precautions to prevent reduced soap efficiency and spotting on dishes and glassware.

Geology & Source: New Jersey Highlands Precambrian gneiss; Triassic Newark Basin calcareous - moderately hard

Other New Jersey Water Reports

Parsippany

≈ 180+ mg/L

🔴 Very Hard

Dover

≈ 120–179 mg/L

🟠 Hard

Morristown

≈ 120–179 mg/L

🟠 Hard

Randolph

≈ 120–179 mg/L

🟠 Hard

Report an Issue

Notice an error or missing data? Help us keep this page accurate. If you spot incorrect water hardness, outdated utility info, or missing details, please let us know.

All reports are reviewed by our team. Thank you for supporting data quality!

Frequently Asked Questions

Is Denville's water safe to drink?

Yes. Denville's water meets all federal safety standards. The hardness is ≈ 120–179 mg/L (Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Denville?

At ≈ 120–179 mg/L (Hard), Denville's water will cause significant limescale on kettles, washing machines, and water heaters. A water softener or descaler is strongly recommended to extend appliance lifespan and reduce energy bills by up to 20%.

How does Denville compare to the USA average?

The USA national average is 151 mg/L. Denville (≈ 120–179 mg/L) is 1 mg/L below the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Denville is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.

Estimated

Water Hardness

Modelled estimate based on state-level USGS geological survey data for this region. No direct USGS Water Quality Portal measurement was matched to this city — the value reflects a statistical range calibrated to the state's dominant rock types and typical source water characteristics.

Estimated

Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.

Estimated

TDS — Total Dissolved Solids

Estimated using a derived ratio from water hardness and regional conductance profiles. TDS in natural water correlates strongly with total mineral content including hardness ions.

Measured

PFAS — Perfluoroalkyl and Polyfluoroalkyl Substances

EPA UCMR5 (5th Unregulated Contaminant Monitoring Rule, 2023–2025) — sum of PFAS compounds detected at the public water system serving this city. A value of 0 indicates the system was sampled with no detection above reporting limits.

Modelled

Lead

Modelled estimate based on the EPA Lead and Copper Rule 90th-percentile tap-sample methodology. No publicly available per-city lead dataset with sufficient national coverage exists. Values are a conservative baseline derived from city population tier and infrastructure age — all estimates are maintained below the EPA action level of 0.015 mg/L.

Calculated

Appliance Lifespan

Calculated from water hardness using a linear degradation model. Baseline lifespans represent soft-water performance (kettle: 8.5 yrs, washing machine: 12.0 yrs, water heater: 15.0 yrs). Hard water mineral scale progressively reduces operational life in direct proportion to hardness concentration.