Toilet Keeps Running? Causes, Quick Fixes & When to Call a Plumber
By King's Cliff Plumbing · Updated 2026-11-02
Why a toilet keeps running
A toilet that runs nonstop is almost always a tank problem: a worn flapper that no longer seals, a fill valve set too high so water spills into the overflow tube, or a chain that's too short and holds the flapper open. Each one lets water trickle from the tank into the bowl, and the fill valve keeps topping it up. Across Tennessee that can waste 200 gallons a day and show up on your water bill fast.
Quick checks before you call
Lift the tank lid and look at the water line – it should sit about an inch below the overflow tube. Press down on the flapper; if the running stops, the flapper is the culprit and a replacement costs a few dollars. Add a few drops of food coloring to the tank and wait 15 minutes; color in the bowl confirms a leaking flapper.
When it's time for a plumber
If a new flapper and fill valve don't solve it, the flush valve seat may be corroded or cracked, which requires pulling the tank. Toilets older than 20 years often have multiple worn parts, and a modern efficient toilet replacement can pay for itself in water savings. Our toilet repair plumbers serve every city in Tennessee with same-day appointments.
Related problems
A toilet that overflows, rocks at the base or flushes weakly points to clogs or seal failures rather than tank parts. Read our guide on sewage smells and slow drains if several fixtures are acting up at once – that's a main line issue, not a toilet issue.