That constant hissing or trickling sound coming from your bathroom isn’t just annoying—it’s also expensive. A running toilet can waste hundreds of gallons of water per day, leading to a massive spike in your South Florida water bill.
At A to Z Statewide Plumbing, we see this issue daily. While some fixes are simple DIY tasks, others require a professional touch. Here are 6 common reasons your toilet keeps running and how to fix it.
1. A Worn-Out Flapper (The #1 Culprit)
The flapper is the rubber seal at the bottom of the tank that lifts when you flush.
The Problem:
Over time, the rubber becomes brittle or covered in mineral deposits, preventing it from creating a tight seal.
The Fix:
Replace the flapper. It’s an inexpensive part available at any hardware store.
2. The Flush Valve Chain is Too Long or Short
The chain connects the flush handle to the flapper.
The Problem:
If the chain is too long, it can get caught under the flapper, preventing it from closing. If it’s too short, it will keep the flapper pulled up slightly.
The Fix:
Adjust the clip on the chain so there is about half an inch of slack.
3. Water Level is Set Too High
Inside your tank, there is an overflow tube. If the water level is higher than this tube, water will constantly pour into it.
The Problem:
The float (the ball or cylinder that rises with the water) is set too high.
The Fix:
Adjust the float screw or clip so that the water level sits about an inch below the top of the overflow tube.
4. A Faulty Fill Valve
The fill valve is the tall tower on the left side of the tank that refills it after a flush.
The Problem:
If the fill valve is old or clogged with debris, it may never fully shut off, even if the float is at the right height.
The Fix:
If adjusting the float doesn’t work, the entire fill valve may need to be replaced.
5. Hard Water & Mineral Buildup
In South Florida, our water is notoriously “hard,” meaning it’s full of calcium and magnesium.
The Problem:
These minerals build up on the flush valve seat (where the flapper sits), creating a rough surface that allows water to leak through.
The Fix:
Clean the valve seat with a scrub sponge or call a pro to install a water softener to prevent this from happening again.
6. A Cracked Flush Valve Tube
While rare, the plastic tube inside the tank can develop a hairline crack.
The Problem:
Even a tiny crack below the water line will cause a slow, constant leak into the bowl.
The Fix:
This usually requires removing the tank from the bowl to replace the entire flush valve assembly—a job best left to a professional.
When to Call A to Z Statewide Plumbing
If you’ve replaced the flapper and adjusted the float, but the water is still running, the issue is likely deeper in the plumbing or requires a tank rebuild.
Don’t Let Your Money Go Down the Drain
If your toilet is acting up or you’ve noticed a sudden jump in your utility bill, contact A to Z Statewide Plumbing today. We offer fast, professional toilet repairs and high-efficiency replacements throughout South Florida.

