Knoxville's water is moderately hard, but the suburbs drink from five different sources. Here is what each utility reports and how to keep glass, chrome and kettles clear.
Ask five neighbors around Knoxville where their water comes from and you can get five answers. The city's utility pulls from the Tennessee River, Maryville from a mountain stream, Farragut from Fort Loudoun Lake, north Knox County from two reservoirs and Oak Ridge from the Clinch River. The mineral film on a shower door depends on which of those reaches your tap.
This guide sorts out the utilities, explains what the published numbers mean and gives the cleaning habits that work for moderately hard and soft water.
Knoxville Utilities Board takes in more than 30 million gallons a day from the Tennessee River and treats it at the Mark B. Whitaker Water Treatment Plant. Its 2025 Water Quality Report lists an average hardness of 94 parts per million, with calcium averaging 26 ppm, a pH of 7.3 and total dissolved solids of 120 ppm.
KUB describes that water as moderately hard, a class it defines as 61 to 120 mg/L. Parts per million and milligrams per liter are the same measure for water, so 94 sits in the middle of the moderately hard band. In practice, that means a faint white haze on glass and chrome that builds over weeks rather than days.
Maryville. The City of Maryville draws from the Little River, which starts in the Great Smoky Mountains. Its 2024 annual average hardness was 56 mg/L, below KUB's moderately hard band, and the city notes that dishwasher and washer settings depend on hardness.
Farragut. First Utility District of Knox County, which serves the Farragut area, draws from Fort Loudoun Lake on the Tennessee River and treats it at a plant rated for 34 million gallons a day.
North Knox County and Powell. Hallsdale-Powell Utility District draws from Melton Hill Lake and Norris Lake and runs from north Knox County into Union County and part of Anderson County.
Oak Ridge. The city's water comes from the Clinch River. Its original plant was built in 1943 above what is now Y-12, and a replacement plant at the intake off Pumphouse Road is designed to treat up to 12 million gallons a day.
If you are not on KUB, look up your own utility's annual water quality report for its hardness figure, since it can differ from the city's.
At around 94 ppm, the signs are mild but steady. Water that dries on a surface leaves its minerals behind, so the spots appear wherever water sits and evaporates.
The best defense is simple: do not let water dry on glass and chrome. A squeegee on the shower door and a towel over the faucet after use prevent most film. Once a week, a mild vinegar solution or a cleaner made for mineral spots, rinsed and dried, keeps up with KUB water easily. Test acids on a hidden spot first, and keep them off natural stone such as marble, which they can etch.
On softer Maryville water, the film is lighter, and the city's note about appliance settings is worth acting on. Check whether your dishwasher has a hardness setting and match it to the published number so you are not overusing rinse aid or detergent.
In a humid Knoxville summer, with July dew points near 68 degrees, wet shower walls stay wet longer. That gives minerals more time to settle, so drying the glass matters more from June through August.
A Recurring House Clean wipes and dries fixtures on every visit, which keeps moderately hard water from building. A One-Time Deep Clean goes further: it treats shower glass for hard water spots and details faucets at the base and handles. It cannot reverse glass that is already etched, which shows as a permanent cloudiness that does not wipe off. For timing and scope, see the deep cleaning guide.
The questions Knoxville homeowners ask most often about this topic, answered plainly.
TotalCare Cleaning will service Knoxville and surrounding areas with background-checked cleaners and is insured up to $1 million. Re-clean guarantee: if we missed something, tell us by the end of the next day and we come back to fix it. Beyond Clean. TotalCare.
