The toilet flapper is a rubber mechanism in your toilet that opens to let water out of the toilet tank when you flush and closes to allow it to refill. The handle pulls a chain connected to the flapper. Then the flapper rises and opens the valve between the tank and the bowl. Flappers deteriorate over time mainly because of the toilet bowl cleaners you drop into the tank or by chemicals used by utilities thus causing your toilet to leak.
A flapper may wrinkle or warp only slightly so that it doesn't have a good seal around the water valve between the toilet tank and the bowl. Even a small leak will let water run all the time without you noticing, which can add up to hundreds of dollars of wasted water over the course of a year.
A flapper may decay so much that it lets enough water through to force the tank to refill. You may hear the water in the toilet run briefly, even when no one has used it recently. That random refill, known as ghost or phantom flushing, is a sign of a significant leak. You may find yourself jiggling the handle to get a good seal on the flapper and stop the water flow.
The good news is, replacing a toilet flapper is an easy do-it-yourself job that doesn't require any tools. It can save you a considerable amount of money as well.
If your toilet flapper is 5 years old – just change it. The time saved will outweigh the cost of fussing with an aged flapper. If the flapper is under 5 years old check the rubber surface for debris. Wipe slime and / or debris from the underside and seat with clean cloth.
If you see warping or waviness of the flat rubber piece then replace it. If you use chlorine tablets in the tank this would be the cause of the warping. Remove the tablet as it damages parts in the tank. Cut excess chain if it is interfering with the seating of the flapper. Makes sure the chain is not too straight. It may lift the flapper from seat. Have anywhere between a ¼ "to ½" slack in chain.
Using the right flapper for your toilet is a very important decision. If your toilet was manufactured on January 1st 1994 and after, your toilet is a 1.6 gallons per flush (gpf) toilet. If your toilet was manufactured before 1994, it is either a 7 gpf, 5 gpf or 3.5 gpf toilet. Choose the right flapper accordingly.