Wentzville Water Hardness & Quality Report (2026)
Water Hardness
15.6 grains per gallon
Source
river
pH Level
8.5
neutral = 7.0
Lead
0.008 mg/L
✓ Below action level
TDS
688.4 mg/L
Est. Daily Cost
$0.71
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 Wentzville, your appliances are currently losing 36% efficiency due to mineral buildup.
| Appliance | In Wentzville | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 1.5 yrs | 8.5 yrs | -82% |
| Washing Machine | 3.7 yrs | 12 yrs | -69% |
| Water Heater | 5 yrs | 15 yrs | -67% |
Regional Water Comparison
How Wentzville compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Wentzville, Missouri | 267.5 mg/L | 8 ppt | 🔴 Very Hard | river |
| Lake Saint Louis, Missouri | 134.5 mg/L | 4.6 ppt | 🟠 Hard | river |
| Dardenne Prairie, Missouri | 289.5 mg/L | 8.5 ppt | 🔴 Very Hard | river |
| O'Fallon, Missouri | 279 mg/L | 8.3 ppt | 🔴 Very Hard | river |
| Saint Peters, Missouri | 137 mg/L | 4.6 ppt | 🟠 Hard | river |
National Benchmark
How Wentzville compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Wentzville | 267.5 mg/L | 🔴 High |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Wentzville's Water Unique?
Local geology and source profile
Wentzville, Missouri, in St. Charles County — one of the fastest-growing cities in Missouri (Wentzville has been among the top fastest-growing US cities for several consecutive years — a major St. Charles County suburban community in the explosive west St. Louis suburban corridor), home of a major General Motors Wentzville Assembly Plant (the GM Wentzville Assembly Plant is one of the largest automotive manufacturing facilities in Missouri — producing Chevrolet Colorado trucks and GMC Canyon trucks; a major economic driver for St. Charles County), a rapidly growing community in the I-70 west St. Louis corridor, and a diverse St. Charles County community with a significant working-class and manufacturing professional population — draws its municipal water supply from the Ozark deep aquifer wells via the City of Wentzville Water Division. Water hardness in Wentzville measures 267.5 mg/L — classified as very hard.
Wentzville's very hard supply reflects the west Missouri Ozark Aquifer's highly calcareous Ordovician dolomite geology. The Ozark Aquifer at Wentzville–St. Charles County draws from: the Ordovician Gasconade Dolomite (highly calcareous dolomite of the Missouri Ozark Dome — one of the most calcareous dolomite formations in the central US); the Ordovician Roubidoux Formation (calcareous sandstone and dolomite); and the Cambrian Eminence and Potosi Dolomite (highly calcareous deep Cambrian dolomite of the Ozark Dome). City of Wentzville applies limited softening, producing the very hard 267.5 mg/L.
At 267.5 mg/L, Wentzville residents face severe hard water challenges. Weekly descaling and appliance protection measures are strongly recommended. City of Wentzville Water Division consistently delivers water meeting all Missouri DNR and EPA Safe Drinking Water Act requirements.
Geology & Source: Groundwater from the Ozark Aquifer (Gasconade Dolomite and Roubidoux Formation) via the City of Wentzville Water Division — the St. Charles County west Missouri St. Charles corridor (Ordovician Gasconade Dolomite and Roubidoux Sandstone — the highly calcareous Missouri Ozark carbonate aquifer; west St. Charles County groundwater supply with limited softening); very hard supply at 267.5 mg/L in St. Charles County.