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Fix a Running Toilet

If you've tried a new flapper to fix your running toilet and it still runs don’t give up hope. Here's a fix that's sure to work.

By the DIY experts of The Family Handyman Magazine

Fix a Running Toilet

If you've tried a new flapper to fix your running toilet and it still runs don’t give up hope. Here's a fix that's sure to work.

Fix for a running toilet

If you hear your toilet refilling too often, or if you hear the steady hiss of running water, the flapper may be leaking. The flapper (aka “flush valve seal”) is the plug that falls against the drain hole (flush valve drain seat) on the bottom of the tank and holds water in until the next time you flush. When flappers or flush valve seats wear out, water trickles out, causing the water valve to open to refill the tank. Usually the fix is simple. Remove the old flapper and take it with you to the hardware store or home center to find a matching replacement. Occasionally a new flapper doesn’t solve the problem. If you’ve tried replacing the flapper but the toilet still runs, the flush valve seat is probably rough or pitted. You can replace the entire flush valve, but it’s a big job. Here’s an easier fix. Look for a flapper kit that contains a flush seat repair. We show a Fluidmaster 555C kit ($7), but others are available. The kit contains a flapper and matching seat that you adhere to the damaged seat with the adhesive provided, as shown. Start by closing the valve on the water line to the toilet by turning it clockwise. Then flush the toilet and hold the flapper open to allow the water to drain from the tank. Use a sponge to mop out the water that remains. Follow the included instructions to install the new valve seat and flapper. The Fluidmaster flapper we show includes a plastic cup that allows you to adjust the length of time the flapper stays open. It’s for toilets that use 3.5 gallons or less for a flush. If your toilet uses more than this, remove the timing cup. Install the new flapper. Then adjust the length of the chain so it’s just slightly slack when the flapper is down. Turn on the water and test the flush. You may have to fiddle with the length of the chain to get the flapper working correctly. When you’re done, cut off the excess chain to keep it from getting stuck under the flapper.

Flush seat repair kit

Flush seat repair kit

Fluidmaster Flush Seat Repair Kit

Take the old flapper with you to find a matching replacement.

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Required Tools for this Project

Have the necessary tools for this DIY project lined up before you start—you’ll save time and frustration.

If you need to shorten the chain, you'll need side cutter pliers or a chain cutter.

Required Materials for this Project

Avoid last-minute shopping trips by having all your materials ready ahead of time. Here's a list.

    • Flush valve repair kit

Comments from DIY Community Members

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September 03, 5:29 PM [GMT -5]

mansanita, I just found one in my city (Portland OR) at George Morlan, a plumbing store. I know, HD doesn't even carry these, and they're SO MUCH LESS WORK (and expense) than the flush valves they tell you are what you need!

January 11, 8:03 AM [GMT -5]

Any local plumbing supply store or home improvement store will carry a universal replacement flapper that will fit your toilet. Menards should have this.

December 11, 8:29 PM [GMT -5]

where can you find the flapper seat repair kits ? I've tried Lowe's and Home depot and they don't carry them . I have to replace the entire old seat units!
Please help, it looks alot easier .

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