Data Desk
27 Missouri Towns Ranked by Severity Score
Real severity score data for 27 engine/data/water towns, pulled July 2026.
Methodology
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Midwest Water News ranked 27 engine/data/water towns in MO, sorted by severity score. Every number below comes straight from the source data, not an estimate.
1. Byrnes Mill (Jefferson County, MO)
Severity score: 9
Byrnes Mill has no city water - you're on PWSD 2 surface water, PWSD 6 wells, or your own private well, and all three carry baggage. If you're on the surface system, every shower steeps you in chlorine byproducts (TTHMs at 173x and haloacetic acids at 300x the health guideline) plus chromium-6, the "Erin Brockovich"...
2. De Soto (Jefferson County, MO)
Severity score: 9
De Soto tap water is VERY HARD - about 21 grains per gallon, roughly three times the level where damage starts. That is the chalky film on your shower glass, the spots you can't wipe off the faucets, soap that won't lather, dry itchy skin, and dull, straw-feeling hair. The same scale silently coats your water heater's...
3. Silex (Lincoln County, MO)
Severity score: 9
Silex made the news for the wrong reason: its water failed the EPA on radium so badly the city handed out bottled water to every resident for nearly two years. Combined radium hit 7.7 pCi/L against a 5 limit, and the city's own report warns it can raise cancer risk over years of drinking. On top of that you are...
4. Barnhart (Jefferson County, MO)
Severity score: 8
Barnhart's tap water is legal, but it is hard (up to 13 grains/gallon) and disinfected with chloramine, so you feel it: dry, itchy skin and dull, straw-like hair after every shower, soap that never fully lathers, chalky scale crusting your faucets and shower glass, and spotty dishes straight out of the rack. That same...
5. Cedar Hill (Jefferson County, MO)
Severity score: 8
Cedar Hill city water runs about 18 grains per gallon - "very hard" - with high alkalinity and a pH of 8.1, so the chalky scale crusting your faucets, the soap that never rinses off, the film on your glassware, and the skin that feels tight and hair that goes brittle after every shower are not in your head - they are...
6. Defiance (St. Charles County, MO)
Severity score: 8
Your Defiance water comes from Missouri River valley wells, and it is very hard - that's the chalky white crust building on your faucets and showerheads, the soap that never rinses off, the film on your glasses, and the reason your skin feels tight and your hair goes dry and brittle. That same scale silently coats the...
7. Elsberry (Lincoln County, MO)
Severity score: 8
Elsberry's tap water passes the legal test but is hard at about 13 grains - that is the chalky scale crusting your faucets, the soap that won't lather, the spotty dishes, and the limescale quietly killing your water heater. You'll feel it as filmy skin and dry, stringy hair after every shower, and see manganese-driven...
8. Flint Hill (St. Charles County, MO)
Severity score: 8
If you're in Flint Hill, you're almost certainly fighting very hard water - up to 16.7 grains. That's the chalky film on your shower glass, the soap that won't lather, the crusty scale eating your faucets and shortening the life of your water heater, plus dry, itchy skin and dull, brittle hair after every shower. The...
9. Foley (Lincoln County, MO)
Severity score: 8
Foley sits in the Mississippi River bottoms, and bottom-land water is the worst kind for your home: hard, iron-heavy, and prone to that rotten-egg sulfur smell. Expect water that typically tests "very hard" (est. 15-25 grains/gallon) - enough to leave chalky scale on every faucet, fight your soap into a film on skin...
10. High Ridge (Jefferson County, MO)
Severity score: 8
High Ridge tap water is drawn partly from the Big River - a river the EPA has Superfund-listed for over a century of lead mining. It's treated to meet legal limits, but the 2025 report shows chlorine byproducts (TTHMs) spiking to 53 ppb, roughly 350x the modern health guideline, plus lead measured as high as 361 ppb...
11. Hillsboro (Jefferson County, MO)
Severity score: 8
Hillsboro tap runs about 19 grains per gallon - rated VERY HARD. That's the chalky scale crusting your faucets and showerheads, the spots that won't wipe off your glasses, soap and shampoo that never lather, dry itchy skin and dull, brittle hair, and a water heater quietly choking on lime that dies years early. On top...
12. House Springs (Jefferson County, MO)
Severity score: 8
House Springs water depends on your street, and neither side is gentle. If you're on the local wells (PWSD No. 6), you've got VERY hard water at ~19 grains - that's the chalky film on your faucets, the spots on every glass, soap that won't lather, dry itchy skin, flat hair, and a water heater quietly dying years early...
13. Innsbrook (Warren County, MO)
Severity score: 8
Your Innsbrook water is hard - about 11 grains a gallon on the public system, and 15-25+ grains if you're on a private well. That is the chalky scale crusting your faucets and showerheads, the soap that never rinses off, the film on your glasses, and the water heater that dies years early. The public supply runs...
14. Labadie (Franklin County, MO)
Severity score: 8
If you live in Labadie, your water is VERY HARD - about 18 grains per gallon of dissolved rock straight out of the ground. That is the chalky film on your faucets and shower glass, the soap and shampoo that never lather, the dull film on your skin and hair, the spots on every dish, and the scale quietly choking your...
15. O'Fallon (St. Charles County, MO)
Severity score: 8
O'Fallon's water is hard and busy. Depending on who bills you, you're looking at 6-10 grains of hardness on treated city water and up to 15-20 grains on raw county and well water - that's the chalky white scale crusting your faucets, the spots on your glasses, the soap that won't lather, and the water heater that dies...
16. Old Monroe (Lincoln County, MO)
Severity score: 8
If you live in Old Monroe, your tap is some of the hardest water in eastern Missouri - around 18 grains per gallon. That is the chalky white crust eating your faucets and showerheads, the film that leaves skin tight and itchy and hair dull and straw-like, and the scale that silently kills water heaters and appliances...
17. Pacific (Franklin County, MO)
Severity score: 8
Pacific runs entirely on groundwater wells, and that water is VERY hard at about 19 grains per gallon - that is the chalky scale crusting your faucets and shower glass, the film that leaves your skin tight and your hair dull and straw-like, and the mineral buildup quietly cooking your water heater to an early death....
18. Pevely (Jefferson County, MO)
Severity score: 8
Pevely's tap water is groundwater pumped from local wells, and it is brutally hard - about 19 grains per gallon, roughly triple the "very hard" line. That is the white crust on your faucets and showerheads, the film that leaves your skin tight and itchy and your hair dull and straw-like, the soap that never quite...
19. St. Clair (Franklin County, MO)
Severity score: 8
St. Clair water is hard - about 14.6 grains a gallon in town, and a brutal 18 grains out on the county district. That is the chalky white crust on your faucets and shower glass, the film that leaves your skin tight and itchy and your hair flat and straw-like, the soap that never really rinses, and the scale silently...
20. Sullivan (Franklin County (straddles the Franklin/Crawford County line), MO)
Severity score: 8
Sullivan's city water comes straight out of deep dolomite wells at roughly 13 grains per gallon - hard enough that you can watch it happen: chalky white scale crusting your faucets and showerheads, spotty glassware, soap and shampoo that won't lather, and a water heater quietly choking on mineral buildup years before...
21. Warrenton (Warren County, MO)
Severity score: 8
Warrenton runs on 100% deep groundwater and the City does NOT soften it - so your tap pours out very hard 16-grain water that crusts white scale on faucets and showerheads, kills soap lather, leaves spots on dishes, makes laundry stiff, and quietly shortens the life of your water heater and appliances. That same...
22. Washington (Franklin County, MO)
Severity score: 8
Washington's city water is VERY hard - about 16 grains per gallon - so you're fighting chalky scale on faucets and shower glass, film that won't rinse off your skin and hair, and a water heater that's quietly crusting over and dying years early. Iron at 0.43 mg/L runs over the federal guideline, which is what stains...
23. Wentzville (St. Charles County, MO)
Severity score: 8
Wentzville water is genuinely hard - 11 to 17 grains a gallon, deep in the "very hard" zone. That's the chalky white crust locking up your faucets and showerheads, the soap that won't rinse off, the filmy skin and dry, brittle hair after every shower, and scale quietly coating the inside of your water heater until it...
24. Winfield (Lincoln County, MO)
Severity score: 8
Winfield's tap water is brutally hard - about 18 grains, double the "very hard" line - so you're scrubbing chalky scale off faucets and glassware, fighting dry, itchy skin and dull, filmy hair, and quietly killing your water heater 15-20% early as scale cakes the tank. It carries more dissolved minerals than the EPA's...
25. Arnold (Jefferson County, MO)
Severity score: 7
Arnold's tap water is hard (about 7-9 grains/gallon) and disinfected with chloramine, which is exactly why your faucets crust over with white scale, your glasses come out spotty, soap won't lather, and your skin and hair feel dry, filmy, and itchy after every shower. That scale silently shortens the life of your water...
26. Augusta (St. Charles County, MO)
Severity score: 7
Augusta tap is hard at about 10.8 grains and runs strongly alkaline (pH 9+), so it chalks up your faucets and showerheads with white scale, leaves spots on glasses, eats through soap, and quietly shortens the life of your water heater. It is legal water, but it carries chlorine disinfection byproducts (TTHMs) at...
27. Cottleville (St. Charles County, MO)
Severity score: 7
Cottleville tap water is hard - roughly 10 to 19 grains per gallon - and you can feel it: filmy skin that never rinses clean, dull flat hair, chalky spots on your dishes and glass shower doors, and crusty white scale building on every faucet and showerhead. That same scale is silently choking your water heater,...