Job book · Entry 02

Your toilet won't stop running.


A running toilet isn't an emergency — it's usually one of three small parts inside the tank. The catch is the water it sends down the drain day and night.

What it usually is

  • 01Flapper not seating — warped, cracked, or chained wrong, so water leaks past it nonstop.
  • 02Fill valve running past the overflow tube because the float is set too high or has gone waterlogged.
  • 03Refill tube stuffed down inside the overflow pipe, siphoning tank water (it should clip near the top, not sit in the pipe).
  • 04Mineral crust on the seat the flapper lands against — more common where the water runs hard.

Safe checks you can do now

  • Take the tank lid off and watch a full cycle — you'll see which part is misbehaving.
  • Put a few drops of food coloring in the tank and wait 15 minutes without flushing; color showing up in the bowl means the flapper is leaking.
  • Check that the chain has a little slack — one or two links, not drum-tight and not a tangled nest.
  • Confirm the water level sits about an inch below the top of the overflow tube; lower it by adjusting the float screw or arm.
  • Close the shutoff under the tank and see if the tank holds level — if it slowly drops, the flapper is your culprit.

Where this stops being DIY

If a new flapper and a float adjustment don't quiet it, or the tank sweats enough to puddle the floor, the flush assembly is due for replacement. A toilet that runs nonstop can move a couple hundred gallons a day — worth fixing this week, not someday.

(256) 415-7610

House-age angle: Toilets from a 1980s-era build are usually on their second or third set of tank parts by now, so one more flapper is normal wear, not a sign the fixture is finished. If the house still has polybutylene supply lines to the toilet — builder-dependent in that era — mention it when the angle stop gets replaced, since the two jobs ride together.

How much water does a running toilet waste?

A small flapper leak can send 30-plus gallons a day past the flapper, and a stuck fill valve can push past 200. It's all clean water going straight down the drain unused.

Can I just shut the toilet off until it's fixed?

Yes — the angle stop under the tank closes the supply, and the tank still holds a flush or two. That's fine for a few days while the parts get sorted, not a permanent plan.

Related work: the fixture repair page · what's in your walls · the fridge card

Call Now — (256) 415-7610Emergency Steps