Lake St. Louis, MO Water Report

Your Lake St. Louis tap is a blend of Missouri River-bottom well water and purchased St. Louis river water, and it comes in hard at about 10.8 grains per gallon. That is the chalky film on your shower glass, the crusty white scale choking your faucets and shower heads, the soap that never quite rinses off your skin and leaves your hair dull and squeaky. That same scale silently coats the inside of your water heater, robbing efficiency and shortening its life. On top of the hardness, the water runs unusually alkaline (pH over 9), which makes it taste flat and soapy and drives even more scum, and it carries chlorine plus disinfection byproducts (TTHMs) you can smell and taste at the tap.

On a private well in Lake St. Louis: Private wells in the surrounding St. Charles/Warren/Lincoln County ring run noticeably harder than the treated city water - typically 15-25+ gpg (estimated from regional DNR/USGS patterns). Common issues: heavy iron and manganese staining (orange/black) in alluvial river-bottom wells, rotten-egg hydrogen sulfide smell from deeper bedrock wells, nitrates from ag runoff and septic, coliform/E. coli (wells have no required disinfection), and naturally occurring radium/radionuclides in the deep eastern-Missouri bedrock aquifers (the city supply already detects radium, so deeper private wells can run higher). Note the former Weldon Spring cleanup site sits in the service area - a real reason to test, though current municipal radium readings are within limits.