Saint Charles Water Hardness & Quality Report (2026)
Water Hardness
8.9 grains per gallon
Source
river
pH Level
7.6
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
170.4 mg/L
Est. Daily Cost
$0.41
energy & soap waste
Source: See methodology section below · 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 Saint Charles, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Saint Charles | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 4.6 yrs | 8.5 yrs | -46% |
| Washing Machine | 8 yrs | 12 yrs | -33% |
| Water Heater | 9.5 yrs | 15 yrs | -37% |
Regional Water Comparison
How Saint Charles compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Saint Charles, Missouri | 152 mg/L | 3.8 ppt | 🟠 Hard | river |
| Bridgeton, Missouri | ≈ 120–179 mg/L | 3.7 ppt | 🟠 Hard | river |
| Maryland Heights, Missouri | 164 mg/L | 5.5 ppt | 🟠 Hard | river |
| Hazelwood, Missouri | ≈ 120–179 mg/L | 6.3 ppt | 🟠 Hard | river |
| Saint Ann, Missouri | ≈ 120–179 mg/L | 3.7 ppt | 🟠 Hard | river |
National Benchmark
How Saint Charles compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Saint Charles | 152 mg/L | 🟠 Moderate |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Saint Charles's Water Unique?
Local geology and source profile
The City of Saint Charles Public Works Utilities Division operates the Saint Charles Public Water System (PWS ID: MO6010707), serving Saint Charles County and surrounding areas. The utility draws water from multiple groundwater wells, including Well #9 (3939 Huster Rd), Well #10 (630 Fountain Lakes Trail), and Well #4 (3892 Huster Rd), all classified as groundwater sources. The system is regulated by the Missouri Department of Natural Resources, which requires regular water quality testing and annual Consumer Confidence Reports.
Saint Charles lies within the Missouri River valley watershed, where alluvial aquifers formed from Quaternary deposits overlie Paleozoic bedrock. The underlying geology includes Ordovician and Devonian limestone and dolomite formations, which are highly soluble and contribute significant dissolved calcium and magnesium to groundwater. This geological setting is responsible for the hard character of the local water supply, typical of the region's karst and limestone terrain.
At 152 mg/L hardness, residents should expect mineral buildup in water heaters, kettles, and plumbing fixtures along with reduced soap and detergent effectiveness. Dishwashers, washing machines, and water heaters are most vulnerable to scale accumulation; regular descaling and a point-of-use or whole-house water softener is recommended to extend appliance lifespan and improve cleaning efficiency. The 2025 Annual Water Quality Report documents carbonate hardness at 152 mg/L (as CaCO₃); pH ranges 9.4–10.2, lead compliance is excellent at 0.001 µg/L, and Chromium-6 has been detected at 1.3 µg/L alongside documented PFAS and disinfection byproducts in some testing.
Geology & Source: Quaternary alluvial aquifers near the Missouri and Mississippi rivers; Paleozoic Ordovician and Devonian limestone and dolomite dissolve calcium and magnesium into groundwater, producing a hard supply in the Missouri River valley
Other Missouri Water Reports
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Frequently Asked Questions
Is Saint Charles's water safe to drink?
Do I need a water softener in Saint Charles?
How does Saint Charles compare to the USA average?
Data Sources & Methodology
Water quality data for Saint Charles is derived from geographic and geological modelling of the surrounding region. No federal monitoring station data was available for this location.
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.
pH
Estimated from regional geology and source water characteristics. pH is correlated with water hardness and local bedrock — values may differ from utility-reported figures.
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.
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.
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.
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.