Dardenne Prairie Water Hardness & Quality Report (2026)
Water Hardness
16.9 grains per gallon
Source
river
pH Level
8.5
neutral = 7.0
Lead
0.009 mg/L
✓ Below action level
TDS
781.1 mg/L
Est. Daily Cost
$0.77
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 Dardenne Prairie, your appliances are currently losing 39% efficiency due to mineral buildup.
| Appliance | In Dardenne Prairie | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 1.5 yrs | 8.5 yrs | -82% |
| Washing Machine | 3 yrs | 12 yrs | -75% |
| Water Heater | 5 yrs | 15 yrs | -67% |
Regional Water Comparison
How Dardenne Prairie compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ 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 |
| Lake Saint Louis, Missouri | 134.5 mg/L | 4.6 ppt | 🟠 Hard | river |
| Saint Peters, Missouri | 137 mg/L | 4.6 ppt | 🟠 Hard | river |
| Wentzville, Missouri | 267.5 mg/L | 8 ppt | 🔴 Very Hard | river |
National Benchmark
How Dardenne Prairie compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Dardenne Prairie | 289.5 mg/L | 🔴 High |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Dardenne Prairie's Water Unique?
Local geology and source profile
Dardenne Prairie, Missouri, in Saint Charles County — a Saint Charles County city adjacent to O'Fallon and Wentzville on the Missouri River in east Missouri — receives its water from the Missouri American Water, drawing from the Missouri River (Saint Charles County) through the east Missouri distribution.
The extremely hard 289.5 mg/L hardness and TDS of 781.1 mg/L reflect the east Missouri Saint Charles County Missouri River supply's extreme dolomitic character — Saint Charles County occupies the Missouri River's confluence zone where the accumulated Ozark Plateau dolomite and Mississippian limestone dissolution reaches peak concentration before the Missouri joins the Mississippi, producing among the highest Missouri River hardness values (compare Fulton MO: 210.5/473; Marshall MO: 161/316 upstream). The Missouri River at Saint Charles County — Ordovician Gasconade Dolomite (dolomitic — primary hardness contributor), Mississippian Burlington Limestone (calcareous — secondary contributor), and Quaternary Missouri River alluvium (calcareous — TDS contributor).
At 289.5 mg/L with TDS 781, Dardenne Prairie's water is extremely hard. A water softener is essential to prevent severe scale damage. A reverse osmosis system is required for drinking water. The PFAS level of 8.5 ppt warrants a certified drinking water filter — the Saint Charles County east Missouri industrial corridor contribute to Dardenne Prairie's elevated PFAS readings.
Geology & Source: Dardenne Prairie in Saint Charles County draws from the Missouri American Water on the Missouri River (Saint Charles County, east Missouri) — the Missouri River at Saint Charles County drains the Ozark Plateau (Ordovician Gasconade Dolomite — dolomitic) and Mississippian Burlington Limestone (calcareous) — Missouri Saint Charles County Missouri River Ordovician-Mississippian dolomitic supply produces extremely hard water at 289.5 mg/L with TDS 781.1 mg/L.