Why Does My Toilet Keep Running? (And How to Stop It)
By JW Moore Plumbing • Updated 2026-09-17
A toilet that keeps running wastes up to 200 gallons of water a day and quietly inflates your water bill.
The flapper is worn or warped
The rubber flapper at the bottom of the tank hardens in Hawaii's warm, humid climate and no longer seals. Water trickles into the bowl and the fill valve keeps cycling. A new flapper is a cheap fix, but the wrong size or shape will keep running.
The float is set too high
If the water level sits above the overflow tube, water pours into the tube constantly. Adjust the float screw or bend the arm so water stops about an inch below the top of the tube.
The fill valve is failing
Mineral deposits and age cause the fill valve to hiss, run intermittently or never shut off. Replacement is usually the answer.
A chain that's too long or short
A chain caught under the flapper holds it open; a chain too short keeps it from sealing. Aim for about half an inch of slack.
When to call a plumber
If you've replaced the flapper and the toilet still runs, or it also rocks, leaks at the base, or overflows, it's time for a professional toilet repair.
Need a Plumber Now?
JW Moore Plumbing offers toilet repair & replacement across Hawaii — 24/7, same day, flat-rate pricing. Call (888) 480-9811 or book online.