Affton Water Hardness & Quality Report (2026)
Water Hardness
11.9 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
$0.54
energy & soap waste
Source: USGS Water Quality Portal · Updated 2026
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 27% efficiency due to mineral buildup.
| Appliance | In Affton | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 2.9 yrs | 8.5 yrs | -66% |
| Washing Machine | 6.1 yrs | 12 yrs | -49% |
| Water Heater | 7.4 yrs | 15 yrs | -51% |
Regional Water Comparison
How Affton compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Affton, Missouri | 204 mg/L | 6.3 ppt | 🔴 Very Hard | river |
| Concord, Missouri | 189 mg/L | 6 ppt | 🔴 Very Hard | river |
| Mehlville, Missouri | 222 mg/L | 6.8 ppt | 🔴 Very Hard | river |
| Webster Groves, Missouri | 257 mg/L | 7.7 ppt | 🔴 Very Hard | river |
| Lemay, Missouri | 183.5 mg/L | 5.8 ppt | 🔴 Very Hard | river |
National Benchmark
How Affton compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Affton | 204 mg/L | 🔴 High |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Affton's Water Unique?
Local geology and source profile
Affton, Missouri, in Saint Louis County — an unincorporated St. Louis County suburb directly south of St. Louis City, adjacent to Lemay and Shrewsbury in the south St. Louis County corridor — receives its municipal water from Missouri American Water, which draws from the Meramec River or the Missouri River through the St. Louis metropolitan water supply system.
The hard 204 mg/L hardness and elevated TDS of 450.6 mg/L reflect the Meramec-Missouri River supply's Ozark Plateau carbonate geological character. The Meramec River drains the Salem Plateau and St. Francois Mountains region of the Ozark Dome — terrain underlain by the Mississippian Burlington-Keokuk Limestone (the dominant Ozark carbonate), the Ordovician Gasconade Dolomite (a thick dolostone), the Ordovician Jefferson City Dolomite, and ultimately the Cambrian Lamotte Sandstone and Cambrian dolomite in the deep Ozark core. The Ozark Plateau's thick Mississippian and Ordovician carbonate sequence produces consistently hard water throughout the Meramec watershed — one of the most carbonate-rich drainage systems in Missouri.
At 204 mg/L, Affton's water is hard — scale builds in kettles and appliances within weeks, dishwashers require rinse aid or softener salt, and bathroom fixtures develop calcium encrustation. Monthly descaling of heating appliances is practical. A water softener is recommended. The PFAS level of 6.3 ppt warrants a certified drinking water filter — the St. Louis industrial legacy (chemical manufacturing, aerospace, defense), the Scott Air Force Base in the broader St. Louis metro region, and the Meramec watershed's industrial legacy contribute to Affton's PFAS readings.
Geology & Source: Affton in Saint Louis County draws from Missouri American Water treating the Missouri River or the Meramec River — the Meramec River drains the Ozark Plateau (Mississippian Burlington-Keokuk Limestone, Ordovician Gasconade Dolomite, and Cambrian carbonates) — Ozark Plateau carbonate drainage produces hard water at 204 mg/L with elevated TDS 451 mg/L in this Saint Louis County Missouri suburb.