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

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

Wilmington Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

river

pH Level

8.5

neutral = 7.0

Lead

0.003 mg/L

✓ Below action level

TDS

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

Appliance	In Wilmington	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 Wilmington compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Wilmington, Ohio	≈ 120–179 mg/L	43.1 ppt	🟠 Hard	river
Xenia, Ohio	≈ 180+ mg/L	0 ppt	🔴 Very Hard	groundwater
Beavercreek, Ohio	≈ 120–179 mg/L	0 ppt	🟠 Hard	groundwater
Lebanon, Ohio	≈ 120–179 mg/L	0 ppt	🟠 Hard	groundwater
Centerville, Ohio	≈ 120–179 mg/L	6.4 ppt	🟠 Hard	river

National Benchmark

How Wilmington compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Wilmington	≈ 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 Wilmington's Water Unique?

Local geology and source profile

Source: RiverTDS: 253.6 mg/LpH: 8.5

The Wilmington City Public Water Supply serves about 13,212 residents in Wilmington, Ohio, drawing its drinking water from Caesar Creek Lake. This surface water reservoir, located about 14 kilometers northwest of the city, is the primary source for the Wilmington City Water Department. The water travels from the Miami Valley watershed to the treatment facility before distribution. The reservoir's location in southwestern Ohio means the water is naturally influenced by the region's geology.

The water originates in the Miami Valley watershed, an area characterized by Ordovician and Silurian carbonate bedrock, specifically limestone and dolomite. These soluble rock formations are common throughout southwestern Ohio and readily dissolve as water flows through them, picking up minerals like calcium and magnesium. This natural process is the reason why water in this region is typically hard.

Homeowners in Wilmington may notice scale buildup in appliances like kettles and water heaters, and reduced effectiveness from soaps and detergents. Potential staining on fixtures is also a common sign of hard water. To combat these issues and protect your plumbing, a water softener is often recommended, especially for systems like washing machines, dishwashers, and hot water heaters. Regular descaling of appliances can also help maintain their efficiency and extend their lifespan.

Geology & Source: Ordovician and Silurian limestone and dolomite; soluble carbonate bedrock dissolves readily, producing hard water

Other Ohio Water Reports

Xenia

≈ 180+ mg/L

🔴 Very Hard

Beavercreek

≈ 120–179 mg/L

🟠 Hard

Lebanon

≈ 120–179 mg/L

🟠 Hard

Centerville

≈ 120–179 mg/L

🟠 Hard

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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 Wilmington's water safe to drink?

Yes. Wilmington'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 Wilmington?

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

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