How to Fix a Running Toilet: A Simple DIY Guide (10-Minute Solution)

Remove the Tank Lid and Identify the Problem

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Start by carefully removing the toilet tank lid and placing it on a flat, secure surface. Flush the toilet and observe the mechanism in action. Look for common issues like a chain that's too short or too long, a worn-out flapper that doesn't seal properly, or a fill valve that doesn't shut off completely. The most common cause of a running toilet is a faulty flapper that doesn't create a proper seal, allowing water to continuously leak into the bowl.

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Check the Flapper

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Inspect the flapper – the rubber seal that lifts when you flush and covers the drain hole at the bottom of the tank. Look for signs of deterioration, warping, or mineral buildup. A good flapper should be flexible but firm, with no cracks or degradation. If the flapper is worn, it won't create a proper seal, allowing water to leak continuously into the bowl.

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Adjust or Replace the Chain

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The chain connecting the flush lever to the flapper should have just a small amount of slack when at rest. If it's too long, it can get caught under the flapper, preventing a proper seal. If it's too short, it won't allow the flapper to close completely. Adjust the chain length by moving the clip to a different link, ensuring about 1/2 inch of slack.

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Replace the Flapper if Necessary

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If the flapper is worn or damaged, it needs replacement. Turn off the water supply valve and flush to empty the tank. Disconnect the chain and remove the old flapper by sliding it off the pegs on the overflow tube. Take the old flapper to the hardware store to ensure you get an exact match, or purchase a universal replacement. Install the new flapper by sliding it onto the pegs and reattaching the chain.

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