DIY: How to Replace a Toilet Flapper Replacing a toilet flapper sounds harder than it actually is. In fact, most homeowners can replace the toilet flapper themselves, and save money in the process! This Blankenships’ Universal Supply guide gives you DIY step-by-step instructions to replacing your toilet flapper. Learn how below! What is a toilet flapper?  A toilet flapper is a piece inside of a toilet tank that lets water go out of the tank and into the bowl when the toilet is flushed. Follow these step by step instructions to replace your toilet flapper: Remove tank lid Remove the tank lid and set aside. Turn off water supply First, turn off the water by closing the shutoff valve. This can be found on the water supply line; turn the handle clockwise until it comes to a halt.  Remove water in toilet tank Flush the toilet to remove the majority of water from the tank. Soak up any remaining water using a cloth or sponge.  Remove old flapper Disconnect the lift chain to remove the old fla