Know what’s actually in your
Middle Tennessee water

Yes. All 17 major utilities in the Tennessee Water Authority guide series met every EPA regulatory standard in 2025 with zero health violations. Safe to drink and safe under EPA law are not the same thing, however. The EWG Tap Water Database identifies contaminants present above health guidelines — even when below legal limits — including disinfection byproducts, chromium-6, and PFAS in some utilities. Knowing which utility serves your address and what it shows above EWG guidelines is the starting point for making an informed filter decision.

It varies significantly by city and water source. Nashville MWS draws from the Cumberland River and measures 5.9 GPG — moderately hard (verified 2025 CCR). Clarksville is similar at 5.67 GPG. Franklin is harder at 7.9 GPG (Harpeth River, verified 2025 CCR). Murfreesboro and Smyrna draw from Stones River and Percy Priest Lake and are estimated at 11–14 GPG — very hard. Rural private wells on limestone aquifers in Williamson, Dickson, and Maury Counties commonly reach 15–20+ GPG. Use our hardness guide and your city guide for a specific number.

It depends entirely on your GPG. At Nashville’s 5.9 GPG, a softener is optional — scale will form slowly and many residents are fine with just a carbon filter. At Franklin’s 7.9 GPG, a softener starts making financial sense when you factor in water heater efficiency loss and appliance scale. At Murfreesboro’s 11–14 GPG, a softener pays for itself within a few years through energy savings alone. For private wells at 15+ GPG, a softener is essentially required. Our softeners vs conditioners guide explains which type is right for your GPG level.

PFAS are per- and polyfluoroalkyl substances — a class of industrial chemicals that persist in the environment and accumulate in the body. EPA set PFOA and PFOS MCLs at 4 ppt in 2024, with a proposed extension to 2031 announced in May 2026. In Middle Tennessee: Milcrofton UD and Spring Hill WD have detected PFOA above EWG’s 0.5 ppt health guideline. Nashville MWS, Lebanon, Smyrna, La Vergne, and Hendersonville have zero PFAS detected. An NSF/ANSI 58 certified reverse osmosis system is the recommended treatment for PFAS-affected utilities. See our full PFAS guide for all 17 utilities.

Yes — significantly in some areas. Your water quality is determined by which utility serves your address, not your city name. Nolensville residents may be on NCGUD (TTHMs 77.53 ppb, zero PFAS) or Milcrofton UD (PFOA above EWG) — the same street can have different water. Thompsons Station is served by six separate utilities. College Grove (ZIP 37046) is split between two utilities with different contaminant profiles. Check your water bill for the utility name, then find it in your city guide. Our interactive map shows utility boundaries across the region.

Tennessee does not require any testing of private well water — you are entirely responsible. At minimum, test annually for coliform bacteria, E. coli, and nitrate. Every three years, add hardness, iron, manganese, and pH. At purchase or every five years, add arsenic and lead. Dickson County well owners should also test for VOCs due to historical industrial activity. Robertson and Maury County wells near agriculture should test for atrazine. See our well water testing guide for county-by-county recommendations and TDEC-certified lab contacts.