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

The USA national average is 151 mg/L. Herrin (≈ 180+ mg/L) is 189 mg/L harder than average.

Herrin Water Hardness & Quality Report (2026)

Water Hardness

very hard

180+ mg/L

Very Hard

estimated · not lab-verified

Source

river

pH Level

8.4

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

514.7 mg/L

Est. Daily Cost

$0.91

energy & soap waste

Source: See methodology section below · Updated 2026

very hard180+ mg/LVery Hard · 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 Herrin, your appliances are currently losing 45% efficiency due to mineral buildup.

Appliance	In Herrin	Soft Water City	Efficiency Loss
Kettle	4.7 yrs	8.5 yrs	-45%
Washing Machine	6.6 yrs	12 yrs	-45%
Water Heater	8.3 yrs	15 yrs	-45%

Regional Water Comparison

How Herrin compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Herrin, Illinois	≈ 180+ mg/L	16.7 ppt	🔴 Very Hard	river
Marion, Illinois	≈ 180+ mg/L	11.2 ppt	🔴 Very Hard	river
Carbondale, Illinois	≈ 180+ mg/L	0 ppt	🔴 Very Hard	river
Mount Vernon, Illinois	≈ 180+ mg/L	29.8 ppt	🔴 Very Hard	river
Cape Girardeau, Missouri	≈ 180+ mg/L	42.8 ppt	🔴 Very Hard	groundwater

National Benchmark

How Herrin compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Herrin	≈ 180+ mg/L	🔴 High
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

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What Makes Herrin's Water Unique?

Local geology and source profile

Source: RiverTDS: 514.7 mg/LpH: 8.4

The City of Herrin, serving Williamson County in southernmost Illinois, purchases its surface water supply rather than drawing from groundwater wells. Identified in EPA records as IL1990400, the municipal utility's administrative offices are located at 300 North Park Avenue in Herrin, IL. The water originates from surface sources within the Southern Illinois watershed system, managed by the utility's Director of Public Works, Thomas E. Somers.

The region's geology is characterized by Paleozoic carbonate formations, primarily Mississippian and Pennsylvanian limestone and dolomite, which are typical of the Illinois Basin. These soluble rock layers naturally increase the dissolved mineral content in both surface runoff and any potential groundwater. Consequently, the area is known for producing very hard water, a common trait across Southern Illinois.

Homeowners in Herrin often notice significant mineral buildup, or scale, on faucets, water heaters, and other appliances. This hardness reduces the effectiveness of soaps and detergents, leading to increased cleaning product use. Appliances like dishwashers and washing machines can suffer reduced lifespan and require more frequent maintenance due to mineral accumulation. Many residents find that installing a whole-house water softening system helps mitigate these issues, preserving appliance longevity and improving cleaning efficiency.

Geology & Source: Paleozoic limestone and dolomite; soluble carbonate rocks dissolve calcium and magnesium, creating hard water

Other Illinois Water Reports

Marion

≈ 180+ mg/L

🔴 Very Hard

Carbondale

≈ 180+ mg/L

🔴 Very Hard

Mount Vernon

≈ 180+ mg/L

🔴 Very Hard

Cape Girardeau

≈ 180+ mg/L

🔴 Very 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 Herrin's water safe to drink?

Yes. Herrin's water meets all federal safety standards. The hardness is ≈ 180+ mg/L (Very Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Herrin?

At ≈ 180+ mg/L (Very Hard), Herrin'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 45%.

How does Herrin compare to the USA average?

The USA national average is 151 mg/L. Herrin (≈ 180+ mg/L) is 189 mg/L above the national average. The softest major city is Scarsdale at just 0.02 mg/L.

Data Sources & Methodology

Water quality data for Herrin 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.