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

The USA national average is 151 mg/L. Affton (67 mg/L) is 84 mg/L softer than average.

Affton Water Hardness & Quality Report (2026)

Water Hardness

67mg/L

Moderately Hard

3.9 grains per gallon

Source

river

pH Level

8.3

neutral = 7.0

Lead

0.006 mg/L

✓ Below action level

TDS

450.6 mg/L

Est. Daily Cost

$0.18

energy & soap waste

Source: See methodology section below · Updated 2026

67mg/L as CaCO₃Moderately Hard

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 Affton, your appliances are currently losing 9% efficiency due to mineral buildup.

Appliance	In Affton	Soft Water City	Efficiency Loss
Kettle	7.4 yrs	8.5 yrs	-13%
Washing Machine	11.1 yrs	12 yrs	-8%
Water Heater	12.9 yrs	15 yrs	-14%

Regional Water Comparison

How Affton compares to its nearest neighbours

City	Hardness	PFAS (ppt)	Risk	Source
▶ Affton, Missouri	67 mg/L	6.3 ppt	🟡 Moderately Hard	river
Concord, Missouri	≈ 180+ mg/L	6 ppt	🔴 Very Hard	river
Mehlville, Missouri	67 mg/L	6.8 ppt	🟡 Moderately Hard	river
Webster Groves, Missouri	≈ 120–179 mg/L	7.7 ppt	🟠 Hard	river
Crestwood, Missouri	≈ 120–179 mg/L	7.6 ppt	🟠 Hard	river

National Benchmark

How Affton compares to the USA average

Benchmark	Hardness	Appliance Risk
▶ Affton	67 mg/L	🟡 Low
USA National Avg	151 mg/L	🟠 Moderate
Scarsdale Top Rated	0.02 mg/L	🟢 None

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What Makes Affton's Water Unique?

Local geology and source profile

Source: RiverTDS: 450.6 mg/LpH: 8.3

Affton, in St. Louis County, Missouri, receives its water from American Water Works' St. Louis Region utility, which serves St. Louis and St. Charles Counties. The supply blends approximately 80% from the Missouri River and 20% from the Meramec River, treated at facilities including the Howard Bend and Meramec treatment plants. Daily production averages 180 million gallons, distributed to over 300,000 customers across the metropolitan area, including suburban communities like Affton, via extensive pipeline networks.

The Missouri River watershed traverses Mississippian Burlington Limestone and Pennsylvanian Cherokee Group formations, while the Meramec River drains Ordovician Everton and Plattin dolomites in the eastern Ozarks karst landscape, including the Gasconade and Roubidoux formations. These soluble carbonate rocks progressively dissolve, yielding substantial dissolved solids, and karst hydrology accelerates mineral pickup — imparting a hard character to the blended supply.

Hard water promotes limescale buildup in pipes, water heaters, and dishwashers, with heaters potentially failing 2–3 times faster without treatment. Laundry feels stiff and soap lathers poorly. A water softener is recommended; regular vinegar descaling of faucets and showers helps manage deposits. The 2025 Consumer Confidence Report confirms compliance with state and federal standards; treatment involves coagulation, sedimentation, filtration, and chloramination. pH typically ranges 7.2–8.0; no PFAS exceedances noted.

Geology & Source: Missouri River over Mississippian Burlington Limestone and Pennsylvanian strata; Meramec River cuts Ordovician Gasconade and Roubidoux dolomites — carbonate dissolution yields hard blended supply; Ozark Plateaus karst accelerates mineral pickup

Other Missouri Water Reports

Concord

≈ 180+ mg/L

🔴 Very Hard

Mehlville

67 mg/L

🟡 Moderately Hard

Webster Groves

≈ 120–179 mg/L

🟠 Hard

Crestwood

≈ 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 Affton's water safe to drink?

Yes. Affton's water meets all federal safety standards. The hardness is 67 mg/L (Moderately Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.

Do I need a water softener in Affton?

Affton's water is moderately hard at 67 mg/L. A water softener is generally not necessary, though a carbon filter can improve taste and remove any remaining chlorine.

How does Affton compare to the USA average?

The USA national average is 151 mg/L. Affton (67 mg/L) is 84 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 Affton 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.