What should I check before replacing toilet tank parts?

Before replacing toilet tank parts, first identify the type of components currently installed in your toilet tank. Check whether the fill valve is bottom-entry or side-entry, what type of flush valve is being used, and how the flushing system is operated, such as by a push button, dual flush button, or toilet handle.

Next, measure the key installation sizes. The fill valve inlet has specific thread size requirements, and the flush valve outlet must match the toilet tank drain hole size. You should also measure the ceramic hole size for the push button or handle, so the new part can be installed correctly.

Before removing any toilet tank parts, always shut off the water supply valve first. If the water supply is not closed, water may spray out when the fill valve or other fittings are removed. Checking the part type, key dimensions, and water shut-off condition before replacement can help avoid installation mistakes and unnecessary leakage problems.