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

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

Superior Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

reservoir

pH Level

7.7

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

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

Appliance	In Superior	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 Superior compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Superior, Wisconsin	≈ 120–179 mg/L	0 ppt	🟠 Hard	reservoir
Duluth, Minnesota	44 mg/L	0 ppt	🟢 Soft	river
Cloquet, Minnesota	≈ 180+ mg/L	31.7 ppt	🔴 Very Hard	groundwater
Hibbing, Minnesota	210 mg/L	0 ppt	🔴 Very Hard	groundwater
North Branch, Minnesota	≈ 180+ mg/L	0 ppt	🔴 Very Hard	groundwater

National Benchmark

How Superior compares to the USA average

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

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What Makes Superior's Water Unique?

Local geology and source profile

Source: ReservoirTDS: 115 mg/LpH: 7.7

Superior Water, Light & Power (SWLP), an ALLETE Company subsidiary, provides water service to the Superior area in Douglas County, Wisconsin. The utility operates water treatment and distribution infrastructure serving the region, drawing from groundwater sources typical of the Lake Superior watershed. Annual water quality reports are published through the utility's website and the Wisconsin Department of Natural Resources, documenting compliance with federal and state drinking water standards for the Superior service area.

Superior's water supply originates from groundwater sources in the Lake Superior watershed region, where Precambrian bedrock underlies the area beneath Pleistocene glacial deposits. As groundwater percolates through these formations and mineral-rich glacial till, it dissolves calcium and magnesium minerals, resulting in a hard water supply. This hard character is typical of Southeastern Wisconsin municipal systems, which can range from 8–35 grains per gallon depending on location relative to the Subcontinental Divide.

At hard water levels, residents can expect mineral scale accumulation on fixtures, reduced soap effectiveness, and buildup in water heaters and appliances over time. Ion-exchange water softening equipment is commonly recommended in the region to extend appliance lifespan and improve household water quality. Regular maintenance of plumbing and appliances is advisable to manage mineral deposits. Superior Water, Light & Power maintains compliance with EPA and Wisconsin DNR drinking water standards, with no significant issues reported by regulators.

Geology & Source: Lake Superior basin; Precambrian bedrock overlain by Pleistocene glacial till — groundwater dissolves calcium and magnesium from limestone and mineral-rich glacial deposits, yielding hard supply

Other Wisconsin Water Reports

Duluth

44 mg/L

🟢 Soft

Cloquet

≈ 180+ mg/L

🔴 Very Hard

Hibbing

210 mg/L

🔴 Very Hard

North Branch

≈ 180+ mg/L

🔴 Very 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 Superior's water safe to drink?

Yes. Superior'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 Superior?

At ≈ 120–179 mg/L (Hard), Superior'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 Superior compare to the USA average?

The USA national average is 151 mg/L. Superior (≈ 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 Superior 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.