Oakville Water Hardness & Quality Report (2026)
Water Hardness
~120–179 mg/L
Hardestimated · not lab-verified
Source
river
pH Level
7.6
neutral = 7.0
Lead
0.002 mg/L
✓ Below action level
TDS
161.4 mg/L
Est. Daily Cost
$0.40
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 Oakville, your appliances are currently losing 20% efficiency due to mineral buildup.
| Appliance | In Oakville | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.8 yrs | 8.5 yrs | -20% |
| Washing Machine | 9.6 yrs | 12 yrs | -20% |
| Water Heater | 12 yrs | 15 yrs | -20% |
Regional Water Comparison
How Oakville compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Oakville, Missouri | ≈ 120–179 mg/L | 3.7 ppt | 🟠 Hard | river |
| Mehlville, Missouri | 67 mg/L | 6.8 ppt | 🟡 Moderately Hard | river |
| Lemay, Missouri | ≈ 120–179 mg/L | 5.8 ppt | 🟠 Hard | river |
| Concord, Missouri | ≈ 180+ mg/L | 6 ppt | 🔴 Very Hard | river |
| Arnold, Missouri | ≈ 120–179 mg/L | 0 ppt | 🟠 Hard | river |
National Benchmark
How Oakville compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Oakville | ≈ 120–179 mg/L | 🟠 Moderate |
| USA National Avg | 151 mg/L | 🟠 Moderate |
| Scarsdale Top Rated | 0.02 mg/L | 🟢 None |
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What Makes Oakville's Water Unique?
Local geology and source profile
Oakville, Missouri is served by Missouri American Water's St. Louis / St. Charles County District (PWSID MO6010716), which supplies water to St. Louis County, St. Charles County, and parts of northern Jefferson County, including the Oakville area. Primary sources are the Missouri River and the Meramec River, with approximately 80% of surface water drawn from the Missouri River and 20% from the Meramec. Water is treated at Missouri American Water's surface-water treatment plants before distribution throughout the service area.
The Missouri River watershed in this region drains a landscape underlain by Mississippian-age limestone and Pennsylvanian-age sandstone and shale, with significant carbonate bedrock exposure. As river water flows over and through these formations, it dissolves calcium and magnesium-bearing minerals, producing a hard supply. Groundwater in the Oakville vicinity is drawn from alluvial aquifers along the Missouri River floodplain, hydraulically connected to the river and similarly influenced by carbonate-rich bedrock, consistently yielding water that is mineral-rich and hard.
At hard water levels, Oakville residents can expect noticeable scale buildup in water heaters, kettles, coffee makers, and dishwashers over time. Showerheads, faucets, and washing machines may also accumulate mineral deposits, reducing efficiency and flow. Regular descaling of appliances and periodic cleaning of aerators and showerheads are recommended. A water softener is generally beneficial to reduce spotting on glassware, improve soap lathering, and extend appliance life. Missouri American Water reports that treated water meets all state and federal requirements; treatment includes coagulation, sedimentation, filtration, and disinfection, with fluoride added to support dental health.
Geology & Source: Missouri River and Meramec River watershed — Mississippian-age limestone and Pennsylvanian sandstone and shale; carbonate dissolution and alluvial aquifers along river valley produce hard mixed supply
Other Missouri Water Reports
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Frequently Asked Questions
Is Oakville's water safe to drink?
Do I need a water softener in Oakville?
How does Oakville compare to the USA average?
Data Sources & Methodology
Water quality data for Oakville 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.