A running toilet is the loudest quiet money-waster in a house — a steady leak can push 200 gallons a day through the bowl, which is a water bill you can hear. The good news: lift the tank lid and you're looking at the whole cast of suspects, and the guiltiest one costs about twelve dollars.
Suspect #1: the flapper. That rubber disc at the tank bottom seals water in between flushes, and years of sitting in water warp it out of shape. The test is the same dye trick from our leak guide: food coloring in the TANK, wait fifteen minutes without flushing, look in the BOWL. Color in the bowl convicts the flapper. Replacement is a ten-minute, no-tools job — shut the supply valve, flush to empty the tank, unhook the old one. Take it to the hardware store so the new one matches; "universal" fits most, not all.
Suspect #2: the chain. Too tight and it holds the flapper slightly open; too loose and the slack tucks under the flapper and breaks the seal. You want just a little slack with the flapper seated. This one's free.
Suspect #3: the float and fill valve. If water is trickling into the overflow tube (the open pipe standing in the middle of the tank), the float is set too high — adjust it down so water stops about an inch below the tube's top. If the fill valve hisses and never quite shuts off, the valve itself is worn; a new one runs $15–25 and installs with basic patience.
The "phantom flush." If the toilet refills by itself at 3am with nobody near it, that's a slow flapper leak draining the tank until the float calls for more. Same dye test, same fix.
When it's not the tank: a toilet that rocks when you sit is a different problem — likely the wax ring under it — and worth attention soon, because that seal is what keeps water and sewer gas out of your floor. And a toilet that clogs constantly despite reasonable use is telling you something about the drain, not the flapper.
The honest line: everything above the floor is genuinely DIY-friendly. If you've swapped the flapper twice and it still runs, the tank hardware is crumbling, or the toilet's as old as the house — we'll give you the straight repair-or-replace answer with the price upfront: (901) 699-7763.
