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Saint Charles Water Hardness & Quality Report (2026)

Water Hardness

104mg/L
Moderately Hard

6.1 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

$0.28

energy & soap waste

Source: USGS Water Quality Portal · Updated 2026

104mg/L as CaCO₃Moderately Hard

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 14% efficiency due to mineral buildup.

ApplianceIn Saint CharlesSoft Water CityEfficiency Loss
Kettle
6.2 yrs
8.5 yrs-27%
Washing Machine
9.8 yrs
12 yrs-18%
Water Heater
11.4 yrs
15 yrs-24%
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Regional Water Comparison

How Saint Charles compares to its nearest neighbours

CityHardnessPFAS (ppt)RiskSource
Saint Charles, Missouri104 mg/L3.8 ppt🟡 Moderately Hardriver
Maryland Heights, Missouri171.5 mg/L5.5 ppt🟠 Hardriver
Hazelwood, Missouri201.5 mg/L6.3 ppt🔴 Very Hardriver
Saint Ann, Missouri100 mg/L3.7 ppt🟡 Moderately Hardriver
Creve Coeur, Missouri251.5 mg/L7.6 ppt🔴 Very Hardriver

National Benchmark

How Saint Charles compares to the USA average

BenchmarkHardnessAppliance Risk
Saint Charles104 mg/L🟡 Low
USA National Avg150 mg/L🟠 Moderate
Badger Top Rated8.5 mg/L🟢 None

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What Makes Saint Charles's Water Unique?

Local geology and source profile

Source: RiverTDS: 170.4 mg/LpH: 7.6

Saint Charles, Missouri, the Saint Charles County seat on the Missouri River — Missouri's oldest town (established 1769 as Les Petites Côtes by French traders), the first Missouri state capital — draws its municipal water supply from the Missouri River via the City of Saint Charles Water Division, treating Missouri River water for the Saint Charles area. Saint Charles sits at the Missouri River's confluence approach to the Mississippi, receiving the full Missouri basin drainage from the Rockies and Great Plains. Water hardness in Saint Charles measures 104 mg/L — classified as moderately hard.

Saint Charles's moderate hardness reflects the Missouri River's diluted chemistry at the lower Missouri–St. Louis reach. Despite draining an enormous calcareous basin (the Great Plains Cretaceous Pierre Shale, Pennsylvanian calcareous formations, and Permian evaporite formations of Kansas and Nebraska), the Missouri River at Saint Charles has a surprisingly moderate hardness. The enormous discharge of the lower Missouri River (one of the highest in North America) dilutes the concentrated mineral input from the upper basin. Additionally, the Missouri River's natural sediment load at Saint Charles (the Missouri is still called the 'Big Muddy' for its suspended sediment) includes clay particles that can adsorb dissolved minerals, slightly reducing the dissolved hardness. The resulting 104 mg/L is moderately hard.

At 104 mg/L, Saint Charles residents encounter moderate scale accumulation. Faucet aerators and showerheads develop deposits after several months — monthly cleaning with citric acid solution is practical maintenance. City of Saint Charles Water Division consistently delivers water meeting all Missouri DNR and EPA Safe Drinking Water Act requirements.

Geology & Source: River supply from the Missouri River via the City of Saint Charles Water Division — the Missouri River basin (Precambrian Rocky Mountain and Great Plains calcareous drainage — Yellowstone, Powder, Cheyenne, Kansas, and Platte River tributaries) in Saint Charles County at the Missouri–Mississippi confluence zone; moderately hard supply at 104 mg/L in Saint Charles County.

Other Missouri Water Reports

Frequently Asked Questions

Is Saint Charles's water safe to drink?
Yes. Saint Charles's water meets all federal safety standards. The hardness is 104 mg/L (Moderately Hard), which is safe to drink. High hardness affects appliances and taste, but poses no health risk.
Do I need a water softener in Saint Charles?
Saint Charles's water is moderately hard at 104 mg/L. A water softener is generally not necessary, though a carbon filter can improve taste and remove any remaining chlorine.
How does Saint Charles compare to the USA average?
The USA national average is 150 mg/L. Saint Charles at 104 mg/L is 46 mg/L below the national average. The softest major city is Badger at just 8.5 mg/L.
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