How to Fix a Running Toilet (And Why It's Costing You Money)

That constant hissing sound from your toilet tank isn't harmless background noise — it's water running straight to your sewer bill. A running toilet can waste a significant amount of water every single day, and most of the time the fix is simple.

Why toilets run

Water continuously flowing from the tank into the bowl usually comes down to one of three things: a worn flapper (the rubber seal at the bottom of the tank), a faulty fill valve, or a flush lever that's bent or misaligned.

How to check if your toilet is running

Listen for hissing or trickling a few minutes after flushing. If you're not sure, add a few drops of food coloring to the tank without flushing — if color shows up in the bowl without flushing, water is leaking past the flapper.

The most common DIY fix: replacing the flapper

• Turn off the water supply valve behind the toilet
• Flush to empty the tank
• Unhook the old flapper (usually clips or a chain)
• Bring it to the hardware store to match a replacement
• Install the new flapper and turn the water back on

This is a fast, inexpensive fix — but if replacing the flapper doesn't stop the running, the fill valve or another internal part may be the real problem.

If the DIY fix doesn't solve it, we handle toilet and fixture repair throughout Greer and the Upstate, usually in under an hour.

Still hearing that hiss? Contact us and we'll get it fixed right.

Carolinas A1 Plumbing Service serves homeowners and businesses throughout Greer, Greenville, Spartanburg, Simpsonville, Taylors, Duncan, Lyman, Easley, Travelers Rest, Mauldin, Fountain Inn, Pickens, and Anderson. See all the areas we cover.