Install the flow restrictor. For some models of fill valve (including this one), there are a handful of flow restrictors that come with it in several colors: black, brown, clear, gray, blue, etc.

Your toilet is always there for you. Once you know how to fix the handle, the flush valve, and the fill valve, you'll be able to help in its time of need.

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.