St. Charles, MO Water Report
St. Charles County · Grade C · Hard · 8.9 grains per gallon
Grade C Hard
Anything over 7 gpg is considered hard. St. Charles runs hard.
If you're on City of St. Charles water, it's legally clean but HARD (about 8.9 grains) and runs at a strangely high pH north of 9.3, so you're fighting chalky scale on faucets and shower glass, spotty dishes, dingy laundry, and a water heater that's quietly crusting up and dying years early. It's chlorinated, carries trace lithium and trace (non-quantifiable) PFAS, and your tap is only as safe as your service line - the city is still mapping old lead lines right now. On a private well in the river bottom, it's a different fight entirely: iron staining everything orange, rotten-egg sulfur smell, much harder water, and real nitrate and radium concerns.
On a private well in St. Charles: Private wells tap the Missouri River alluvial aquifer (~98-116 ft). Classic problems: orange/red iron staining on fixtures and laundry (the #1 visible complaint - iron, manganese and sulfate routinely exceed the secondary limit per USGS), black manganese staining, hydrogen-sulfide rotten-egg smell, very high hardness and heavy scale, agricultural nitrate (real Blue-Baby infant risk), surface-infiltration bacteria/coliform, and naturally occurring radium/uranium - amplified near the documented Weldon Spring legacy site (elevated uranium, radium, nitrate, fluoride, sulfate, lithium, molybdenum, strontium).
Data: verified municipal + lab reports for St. Charles, compiled 2026. (confidence: verified)