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

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

Eureka Water Hardness & Quality Report (2026)

Water Hardness

very hard

180+ mg/L

Very Hard

estimated · not lab-verified

Source

river

pH Level

7.1

neutral = 7.0

Lead

0.009 mg/L

✓ Below action level

TDS

763.5 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 Eureka, your appliances are currently losing 45% efficiency due to mineral buildup.

Appliance	In Eureka	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 Eureka compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Eureka, Missouri	≈ 180+ mg/L	0 ppt	🔴 Very Hard	river
Wildwood, Missouri	≈ 180+ mg/L	4.1 ppt	🔴 Very Hard	river
Ballwin, Missouri	≈ 180+ mg/L	3.3 ppt	🔴 Very Hard	river
Manchester, Missouri	≈ 120–179 mg/L	4.6 ppt	🟠 Hard	river
Chesterfield, Missouri	≈ 120–179 mg/L	10.1 ppt	🟠 Hard	river

National Benchmark

How Eureka compares to the USA average

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

Local geology and source profile

Source: RiverTDS: 763.5 mg/LpH: 7.1

Missouri American Water supplies Eureka, Missouri, drawing its water from the Ozark Plateau aquifer system. This groundwater source is treated and distributed through the utility's infrastructure, ensuring compliance with federal and state Safe Drinking Water Act standards. The water originates deep within the earth, tapping into ancient carbonate formations that define the region's hydrogeology. Residents receive a supply carefully managed by MO American Eureka.

The water's journey begins in the Ozark Plateau aquifer, which is primarily composed of Ordovician-age dolomite and limestone bedrock. This geological setting, particularly the highly soluble Gasconade and Eminence Dolomites, readily dissolves calcium and magnesium minerals as water percolates through the rock layers. This natural geological process is characteristic of the Missouri Ozarks, yielding a supply that is naturally very hard.

Homeowners will likely notice the effects of this hard water on their appliances. Significant scale buildup is common in water heaters, dishwashers, and washing machines, which can shorten their lifespan and reduce efficiency. You'll also find that soaps and detergents don't lather as easily, meaning you'll need to use more product for cleaning. To combat these issues and protect your plumbing, installing a whole-house water softener is a highly recommended solution. Regular maintenance of such systems is key for optimal performance.

Geology & Source: Ozark Plateau aquifer system; Ordovician dolomite and limestone (Gasconade and Eminence Dolomites) produce very high hardness

Other Missouri Water Reports

Wildwood

≈ 180+ mg/L

🔴 Very Hard

Ballwin

≈ 180+ mg/L

🔴 Very Hard

Manchester

≈ 120–179 mg/L

🟠 Hard

Chesterfield

≈ 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 Eureka's water safe to drink?

Yes. Eureka'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 Eureka?

At ≈ 180+ mg/L (Very Hard), Eureka'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 Eureka compare to the USA average?

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