Blasted toilet won’t stop running, help!

Q: I’m a little annoyed right now, because every 20 minutes or so, all day and night, the toilet will suddenly start running. It will fill for about a minute and then shut off with that characteristic “clunk.” It’s driving me nuts; how do I stop it? — A.N., via e-mail

A: It’s time to dive into that toilet tank and check for leaks! OK, you don’t literally have to dive in, but it’s clear that the tank is filling up with water, and then the water is slowly leaking out. Find out where the leak is occurring, fix it, and your days and nights will be clunk-free.

First, check the exterior of the tank. Are there any cracks or visible moisture on the tank or connecting water pipe or hose?

•If the tank is cracked, it needs to be replaced; this will run you from $50 to $250 or more.

•If the connector is leaking, you may simply need to replace the washers — or, if using a flexible hose, the entire assembly — which costs only a few dollars.

If no problems are visible outside, check the interior of the tank. Turn off the water supply (typically at the wall directly beneath the tank — otherwise you may have to turn off the main water supply).

•Remove the lid of the tank and flush the toilet, watching the water as it drains and observing the behavior of the tank hardware. Once the tank is empty, inspect the hardware, lifting the tank ball and flapper valve.

•In many cases, the culprit in a leaky tank is an improperly closed flapper valve (the large rubber stopper at the bottom of the tank that lets water into the toilet bowl).

•Make sure the lift arm (or chain) that connects the ball and the flapper valve is properly connected, so that the valve opens and closes completely.

•A lift arm can be adjusted by bending it slightly; a chain by hooking excess links to the connecting wire to take up slack (or removing them, to create slack).

•Check all connections for mineral buildup or rust, and look at any plastic or rubber materials to see if they are deteriorating. Corroded hardware must be replaced; complete kits are available at your hardware store.