What is the most common toilet problem?

A running toilet, usually caused by a worn flapper — the rubber seal at the bottom of the tank. It is a $10 to $15 part and a 10-minute fix, and it is also the most common hidden cause of a high water bill.

How do I know if it is the flapper or the fill valve?

Put a few drops of food coloring in the tank and wait 10 minutes without flushing. If color seeps into the bowl, the flapper is leaking. If the water stays clear but you hear the valve cycle, or water runs into the overflow tube, the fill valve or float height is the problem.

When should I call a plumber for a toilet?

Call a pro if the bowl overflows repeatedly after plunging and augering, if multiple fixtures gurgle at once, or if water leaks from the base every flush after resetting the wax ring. Those point past the toilet to the drain line, vent, or flange.

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Toilet troubleshooting — quick answers

What’s the most common toilet problem?

A running toilet, and the usual culprit is a worn flapper — the rubber seal at the bottom of the tank. It’s a $10–$15 part and a 10-minute fix, and it’s also the #1 hidden cause of a high water bill.

How do I know if it’s the flapper or the fill valve?

Put a few drops of food coloring in the tank and wait 10 minutes without flushing. If color seeps into the bowl, the flapper is leaking. If the tank water stays clear but you hear the valve cycle on and off, or the water keeps running into the overflow tube, the fill valve (or float height) is the problem.

When should I call a plumber instead of DIYing it?

Call a pro if the bowl overflows repeatedly after plunging and augering (a deeper drain or vent blockage), if multiple fixtures gurgle at once (possible main-line issue), or if water leaks from the base every flush after you’ve reset the wax ring. Those point past the toilet itself.

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