Oakville Water Hardness & Quality Report (2026)
Water Hardness
5.8 grains per gallon
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
$0.27
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 Oakville, your appliances are currently losing 13% efficiency due to mineral buildup.
| Appliance | In Oakville | Soft Water City | Efficiency Loss |
|---|---|---|---|
| Kettle | 6.3 yrs | 8.5 yrs | -26% |
| Washing Machine | 9.9 yrs | 12 yrs | -17% |
| Water Heater | 11.6 yrs | 15 yrs | -23% |
Regional Water Comparison
How Oakville compares to its nearest neighbours
| City | Hardness | PFAS (ppt) | Risk | Source |
|---|---|---|---|---|
| ▶ Oakville, Missouri | 100 mg/L | 3.7 ppt | 🟡 Moderately Hard | river |
| Mehlville, Missouri | 222 mg/L | 6.8 ppt | 🔴 Very Hard | river |
| Lemay, Missouri | 183.5 mg/L | 5.8 ppt | 🔴 Very Hard | river |
| Concord, Missouri | 189 mg/L | 6 ppt | 🔴 Very Hard | river |
| Arnold, Missouri | 250.5 mg/L | 7.5 ppt | 🔴 Very Hard | river |
National Benchmark
How Oakville compares to the USA average
| Benchmark | Hardness | Appliance Risk |
|---|---|---|
| ▶ Oakville | 100 mg/L | 🟡 Low |
| USA National Avg | 150 mg/L | 🟠 Moderate |
| Badger Top Rated | 8.5 mg/L | 🟢 None |
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What Makes Oakville's Water Unique?
Local geology and source profile
Oakville, Missouri, an unincorporated community in south St. Louis County — a major south St. Louis County suburban community (Oakville is one of the largest unincorporated communities in the St. Louis metro area — a primarily residential, middle-class south St. Louis County community), known for high-quality public schools in the Mehlville School District (Oakville High School is the largest high school in south St. Louis County), a diverse St. Louis County community with a significant middle-class and working-class population, and adjacent to Arnold and Imperial in the Missouri–Jefferson County border corridor — draws its municipal water supply from the Missouri River via Missouri American Water. Water hardness in Oakville measures 100 mg/L — classified as moderately hard.
Oakville's moderate hardness reflects the Missouri American Water supply and south St. Louis County distribution characteristics. The Missouri River and Mississippi River supply at the Missouri American Water service zone draws from: the Missouri River alluvial aquifer and the Ordovician–Silurian dolomite of the Missouri Ozark Dome margin (calcareous dolomite). Missouri American Water treatment produces the moderate 100 mg/L, representing effective treatment of a calcareous source — substantially softer than the raw Missouri or Mississippi River water.
At 100 mg/L, Oakville residents encounter moderate scale accumulation. Monthly cleaning with citric acid solution is recommended. Missouri American Water consistently delivers water meeting all Missouri DNR and EPA Safe Drinking Water Act requirements.
Geology & Source: River supply from the Missouri River (Eureka supply via Missouri American Water) and Mississippi River via St. Louis MSD via the Missouri American Water — the St. Louis County south Missouri Jefferson County border corridor (Ordovician–Silurian calcareous dolomite and Devonian calcareous limestone of the Missouri Ozark Dome margin; Missouri American Water south St. Louis distribution); moderately hard supply at 100 mg/L in St. Louis County.