I replaced the fill valve in my Kohler toilet with a Kohler fill valve (K-GP1083167). You need to determine which parts are compatible for the toilet you are working on.

Once your toilet flushes, the fill valve, well, starts filling it back up. “They didn’t come up with complicated names when they named the parts of a toilet,” Sebestyen says.

There are three likely culprits that can cause a toilet to run continuously — the float, flapper, or fill valve. Luckily, each is easy to replace.