Well water vs. city water: what 30 years of testing taught me
Here is the one thing I tell every well owner the first time I sit down at their kitchen table: nobody is checking your water but you. A city or public water district has to file a report every year. A private well has none of that. No inspector, no lab, no piece of mail telling you what changed. Whatever is in that water is between you, the ground, and whoever tests it, and most people never do.
After 30 years of testing both kinds of water all over St. Charles, St. Louis, Jefferson, Lincoln, Warren and Franklin counties in Missouri, and Madison and St. Clair counties in Illinois, here is what actually separates the two, and what I've learned to look for.
Iron and sulfur are the first thing a well owner notices
If you're on a shallow well anywhere in the river bottoms, iron is usually the first complaint I hear, and it's almost never subtle. In the American Bottoms aquifer that runs under Alton, Godfrey, Granite City, Edwardsville and Wood River, USGS testing has measured iron as high as 82,000 micrograms per liter in raw well water. City water doesn't have that problem because a treatment plant is pulling it out before it ever reaches a tap. A well has no such plant. That iron is what turns your sinks and toilets rust-orange, stains laundry, and gives water that metallic taste people describe as "drinking a penny." Pair it with hydrogen sulfide, the rotten-egg smell that shows up in deeper, lower-oxygen wells across almost every county we serve, and you have the two most common calls I get.
Bacteria is the risk nobody thinks to ask about
Hardness and staining get the complaints, but bacteria is the one that actually worries me. A statewide Missouri survey of private wells found 56% tested positive for total coliform bacteria, and 22% tested positive for E. coli. That is not a random shallow well somewhere far away. That is roughly one in five private wells in this state carrying E. coli, and the only way an owner finds out is a lab test, because you cannot see, smell, or taste it. I recommend annual bacteria testing for every well owner, full stop, and UV treatment for anyone whose test comes back positive.
Some of this ground carries its own history
A few spots in our service area have a well story that goes beyond the usual iron and hardness. Silex, in Lincoln County, had city water fail the EPA's radium limit so badly the state handed out bottled water to residents for close to 20 months, with combined radium measured at 7.7 pCi/L against a 5 pCi/L limit. Nearby Winfield, Old Monroe, Moscow Mills and Troy sit on the same radium-bearing deep aquifer, and their public wells run 72 to 91 percent of that same legal limit. If you're on a private well in that stretch of Lincoln County and you've never tested for radium, Silex is exactly why you should.
Southwest Jefferson County carries a different history. Byrnes Mill, Cedar Hill, De Soto, Festus, Hillsboro, House Springs and High Ridge all sit inside or next to the Southwest Jefferson County Mining Superfund Site, a legacy of more than a century of lead mining. The EPA tested 1,414 private properties in that footprint and found 147 of them, about 10.4%, over the health limit for lead, cadmium, arsenic or barium. That program is still active, and it is specifically testing private domestic wells, because city water in those same towns is regulated and reported while the wells never were.
And out along the Missouri River near Labadie, Ameren's unlined coal ash ponds have leaked arsenic into floodplain groundwater at roughly 3.5 times the federal drinking water limit. Ameren tests its own monitoring wells around that plant. It does not test the residential wells next door.
City water isn't a free pass either
I don't want to leave city water customers thinking they're in the clear. Chlorine and chloramine disinfection create byproducts called trihalomethanes and haloacetic acids, and in a lot of the towns we serve those numbers run well above the health guidelines that groups like the Environmental Working Group recommend, even while the water is fully legal. Legal just means a utility hit a limit written into a rule 20 years ago. It doesn't mean the water is soft, and it doesn't mean there's nothing left worth filtering out.
What I actually recommend
For a well: start with a full test covering bacteria, nitrates, iron, hardness and pH at minimum, add radium or arsenic testing if you're in one of the areas above, then build the system around what the results actually show. That's usually some combination of a water softener for hardness, an iron and sulfur filter for staining and smell, UV treatment if bacteria shows up, and reverse osmosis at the kitchen tap for anything dissolved that the rest of the system doesn't catch.
For city water, a whole-house softener plus a carbon or reverse osmosis system at the tap handles the chlorine taste, the disinfection byproducts, and whatever hardness your city isn't already treating. Either way, the fix starts with knowing your actual numbers, not a countywide guess.
Related reading: see how these same 57 towns stack up in the hardest water towns we serve, ranked by the numbers, and what that hardness is costing you in what hard water actually costs you every year.
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