The flapper valve is responsible for water regulation from the tank of the toilet to the bowl. When it isn’t working properly, you can have a running toilet.
Most flapper manufacturers have created universal designs that work with almost every toilet. That means you just need to determine the size of flapper that is required, along with the frame or type that may be model-specific.
There are two types of flappers: flexible and solid. Check to see which type your toilet has currently. Flexible flappers are made from rubber and will stretch to fit an oddly-shaped flush valve. Solid flappers are made from a high-quality plastic.
Check the frame of the flapper to see if it is flexible or if it is rigid. If you’re not sure, refer to the manufacturing specifications of the toilet, which can usually be found on the toilet brand’s website.
How to Determine the Correct Flapper Size
Most toilets will have a 2-inch drain or a 3-inch drain. Standard flappers of both types are available for these common sizes, though flexible 3-inch flappers can sometimes be difficult to find.
To measure for the correct size, you will need to lift or remove your current flapper. Then measure the diameter of the flush valve opening that has been exposed. Take that measurement and use it to find the correct replacement flapper.
Some older toilets may have different sizes. Although uncommon, you can still find the unique replacement flapper that will be necessary for a proper repair. Uncommon sizes, however, do tend to cost more than the standard sizing options.
Which Type of Flapper is Required?
Flappers may also be adjustable or non-adjustable, depending upon the flushing capacity of the toilet.
If the toilet was manufactured before 1994, then a non-adjustable flapper is required as older toilets may be designed to hold up to 5 gallons of water in the tank. Even “environmentally friendly” toilets from pre-1994 hold up to 3.5 gallons, which makes the non-adjustable flapper mandatory.
Toilets manufactured after 1994 may come with an adjustable flapper. These are usually designed to work with toilets that flush at 1.3 or 1.6 gallons per flush.
By knowing the age of the toilet, the frame of the flapper, and the size of the flush valve opening, you will be able to successfully determine the correct size of replacement flapper for your toilet.