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

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

Clayton Water Hardness & Quality Report (2026)

Water Hardness

very hard

180+ mg/L

Very Hard

estimated · not lab-verified

Source

groundwater

pH Level

7.8

neutral = 7.0

Lead

0.003 mg/L

✓ Below action level

TDS

259.7 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 Clayton, your appliances are currently losing 45% efficiency due to mineral buildup.

Appliance	In Clayton	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 Clayton compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Clayton, Missouri	≈ 180+ mg/L	4.7 ppt	🔴 Very Hard	groundwater
University City, Missouri	≈ 120–179 mg/L	5.3 ppt	🟠 Hard	river
Webster Groves, Missouri	≈ 120–179 mg/L	7.7 ppt	🟠 Hard	river
Overland, Missouri	≈ 120–179 mg/L	4.8 ppt	🟠 Hard	groundwater
Affton, Missouri	67 mg/L	6.3 ppt	🟡 Moderately Hard	river

National Benchmark

How Clayton compares to the USA average

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

Local geology and source profile

Source: GroundwaterTDS: 259.7 mg/LpH: 7.8

Missouri American Water supplies the City of Clayton and much of St. Louis County with water drawn primarily from the Missouri River and Mississippi River. These vast surface water sources are treated at the Howard Bend Treatment Plant and other regional facilities. The utility serves over 1.5 million people, blending river water with some groundwater from local wells. The watershed encompasses the extensive Midwestern plains and the Ozark highlands, which are characterized by limestone deposits.

The water's journey begins in the Missouri River Alluvial Aquifer and the Ozark Plateaus aquifer system, influenced by ancient bedrock. Formations like the St. Louis Limestone and Kimmswick Limestone, dating back to the Ordovician period, are key. As water percolates through the Ozark Plateaus karst terrain and fractures in these Paleozoic carbonate-rich layers, it dissolves significant amounts of calcium and magnesium. This natural leaching process from sedimentary rocks is what gives the water its characteristically hard quality.

Homeowners will likely notice the effects of this hard water on their plumbing and appliances. Scale buildup is common, reducing the efficiency and lifespan of water heaters, dishwashers, and washing machines. You might also find faucet aerators and showerheads clogging frequently, leading to reduced water flow and unsightly stains on fixtures. To combat this, regular descaling with vinegar or installing a whole-home water softener is highly recommended to protect your home's systems and improve how soap lathers.

Geology & Source: Missouri River Alluvial Aquifer; Ozark Plateaus aquifer system; St. Louis Limestone and Kimmswick Limestone; carbonate-rich bedrock layers and karst terrain produce a hard supply

Other Missouri Water Reports

University City

≈ 120–179 mg/L

🟠 Hard

Webster Groves

≈ 120–179 mg/L

🟠 Hard

Overland

≈ 120–179 mg/L

🟠 Hard

Affton

67 mg/L

🟡 Moderately 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 Clayton's water safe to drink?

Yes. Clayton'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 Clayton?

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

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