A toilet that refills for a few seconds every so often may have a
flapper or fill-valve problem. The water disappears into the bowl, so
there’s no puddle to draw your attention. I suggest listening after the
tank has finished filling and checking the water bill if usage seems
odd.
Look inside the tank without forcing any parts. Is the water level
above the overflow tube? Does the flapper seat cleanly? A few drops of
food coloring in the tank, without flushing, can reveal water moving
into the bowl if color appears there later. EPA WaterSense
explains common toilet leak checks. Follow the toilet manufacturer’s
instructions when replacing parts and avoid in-tank chemical tablets
that the manufacturer prohibits.
A toilet that rocks, has damp flooring at the base, or shows staining
below is a different issue. Don’t keep using it while a seal or subfloor
may be wet. Have a qualified plumber evaluate the leak and any damaged
material. A clogged toilet, too, should not be treated with a succession
of harsh chemicals; a recurring blockage warrants a proper
diagnosis.
I keep plumber contacts on Helpful
Resources. My Homeowner
Tools & Supplies page includes leak detection and basic
maintenance ideas. An inexpensive replacement part is useful only after
you’ve identified which part is failing.