Check the water supply valve and open it fully
Inspect the flush handle and chain for looseness or breakage
Replace a damaged flapper or flush valve seal
Clear any clog with a plunger or toilet auger
Clean or replace a faulty fill valve
Adjust the float if the tank overfills or does not fill
Tighten loose tank bolts and supply line connections
Replace a cracked tank or bowl if leaking
Seal leaking base bolts or wax ring if water appears at the base
Clean mineral buildup from jets and siphon holes
Replace worn gaskets or washers in the tank
Call a plumber if the problem persists