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

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

Coralville Water Hardness & Quality Report (2026)

Water Hardness

hard

~120–179 mg/L

Hard

estimated · not lab-verified

Source

groundwater

pH Level

7.9

neutral = 7.0

Lead

0.008 mg/L

✓ Below action level

TDS

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

Appliance	In Coralville	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 Coralville compares to its nearest neighbours

City	Hardness	Risk	Source
▶ Coralville, Iowa	≈ 120–179 mg/L	🟠 Hard	groundwater
Iowa City, Iowa	50 mg/L	🟢 Soft	river
North Liberty, Iowa	≈ 120–179 mg/L	🟠 Hard	groundwater
Cedar Rapids, Iowa	≈ 180+ mg/L	🔴 Very Hard	mixed
Marion, Iowa	≈ 120–179 mg/L	🟠 Hard	groundwater

National Benchmark

How Coralville compares to the USA average

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

Local geology and source profile

Source: GroundwaterTDS: 412 mg/LpH: 7.9

The Coralville Municipal Water System serves Coralville in Johnson County, Iowa, treating an average of 2.4 million gallons of drinking water per day. Water is sourced exclusively from local groundwater wells in the Silurian aquifer, with no surface water components. The utility manages over 6,300 service connections and can be reached at 319-248-1770 for inquiries or testing.

Recharge occurs locally via precipitation infiltrating the karst landscape above the Silurian dolomite and limestone formations that underlie eastern Iowa. These Paleozoic-era carbonate rocks promote dissolution of calcium and magnesium into the aquifer, imparting a hard character to the groundwater. Thin overburden soils and karst features such as sinkholes create slight vulnerability to surface contaminants — including spills or leaking tanks — through fractures in the bedrock, contrasting with softer glacial drift areas elsewhere in the state.

Hard water in Coralville causes scale buildup in pipes, water heaters, dishwashers, and washing machines, reducing efficiency and lifespan; boilers and coffee makers suffer most, increasing energy costs by up to 20–30%. Regular deliming of appliances every 6–12 months is advised. A water softener is recommended for households to prevent scaling, extend equipment life, and improve soap efficiency; flush taps for 15–30 seconds after stagnation. Coralville's water meets all EPA legal limits, though two contaminants exceed health-based MCLGs; a cost-share filtration program up to $1,000 is available for vulnerable groups concerned about lead exposure.

Geology & Source: Eastern Iowa karst terrain — Silurian dolomite and limestone aquifer; carbonate bedrock dissolves readily, releasing calcium and magnesium to produce hard groundwater; thin soils over fractures allow surface contaminant risk

Other Iowa Water Reports

Iowa City

50 mg/L

🟢 Soft

North Liberty

≈ 120–179 mg/L

🟠 Hard

Cedar Rapids

≈ 180+ mg/L

🔴 Very Hard

Marion

≈ 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 Coralville's water safe to drink?

Yes. Coralville'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 Coralville?

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

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