To fix a running toilet, remove the tank lid and check three parts: the flapper (the rubber seal at the bottom of the tank), the float (which sets the water level), and the fill valve (which refills the tank). A worn flapper causes most running toilets and costs about $5–$10 to replace — no plumber required for the basic fix. This guide walks you through all five steps in order, from most likely cause to least.
Don’t put this one off: a running toilet can waste 200 or more gallons of water per day. At Tampa Bay water and sewer rates, that can quietly add hundreds of dollars to a quarterly utility bill. If your bill already spiked, see our guide to why your water bill is so high.
Why Your Toilet Keeps Running
Every running toilet comes down to the same problem: water is escaping the tank, so the fill valve keeps refilling it. There are only three common escape routes:
- A worn or misseated flapper. The rubber flapper hardens, warps, or collects mineral deposits over time, so it no longer seals against the flush valve. Water seeps into the bowl continuously. This is the most common cause.
- The water level is set too high. If the float is adjusted too high, water pours over the top of the overflow tube nonstop, and the fill valve never shuts off.
- A failing fill valve. Sediment or a worn seal inside the fill valve keeps it from closing fully, so the tank slowly overfills.
Before You Start: 2-Minute Prep
- Remove the tank lid and set it somewhere safe — porcelain lids crack easily.
- Find the shut-off valve on the wall behind the toilet. You don’t need to close it to diagnose, but you’ll want it for repairs. (If it’s stuck or you can’t find it, here’s how to turn off the main water supply to your house.)
- Flush once with the lid off and just watch. Seeing where the water goes tells you which fix below you need.
Step 1: Check the Flapper and Chain
Look at the chain connecting the flush handle to the flapper. It should have about a half inch of slack. Too tight, and the flapper can’t seal; too loose, and it can get pinned under the flapper. Adjust the clip on the chain if needed.
Next, press down gently on the flapper with a stick or gloved hand. If the running sound stops, the flapper is your problem. Turn off the water, flush to empty the tank, unhook the old flapper, and take it to the hardware store to match it exactly. Snap the new one on, reconnect the chain, and turn the water back on. Total cost: about $5–$10.
Step 2: Adjust the Float (Water Level Too High)
Look at the overflow tube — the open vertical pipe in the middle of the tank. If water is trickling into the top of it, the water level is set too high. The correct level is about 1 inch below the top of the overflow tube. Most modern fill valves have an adjustment screw on top: turn it counterclockwise to lower the float. On older ballcock-style valves, gently bend the float arm downward. Flush and confirm the water now stops below the tube.
Step 3: Clean the Fill Valve
If the tank keeps refilling and the flapper and float check out, sediment inside the fill valve is likely holding it open. Turn off the water, flush, then remove the fill valve cap (most twist off counterclockwise while you press down). Inspect the rubber seal underneath and rinse away any grit. Hold a cup over the valve and briefly turn the water on to flush debris out of the valve body, then reassemble.
Step 4: Replace the Flapper (If Cleaning Didn’t Work)
Flappers are wear items — in Florida, chlorinated water and in-tank cleaner tablets break down the rubber faster. If your flapper looks warped, feels gummy, or leaves black residue on your fingers, replace it even if it “mostly” seals. A flapper that leaks slowly causes the classic toilet that runs intermittently — the tank refills for a few seconds every 20–40 minutes, often at night.
Step 5: Replace the Fill Valve
If the valve still won’t shut off after cleaning, replace the whole fill valve — about $15–$25 and 30 minutes:
- Turn off the water at the shut-off valve and flush to empty the tank. Sponge out the remaining water.
- Disconnect the supply line from the bottom of the tank and unscrew the fill valve lock nut.
- Lift out the old valve, set the new one to the same height, and seat its washer inside the tank.
- Hand-tighten the lock nut, reconnect the supply line, turn the water on, and set the water level 1 inch below the overflow tube.
When to Call a Plumber
Call a professional if the toilet still runs after a new flapper and fill valve, if the shut-off valve is seized or leaking, if the tank bolts weep water onto the floor, or if the toilet also flushes slowly or gurgles — those symptoms point past the tank hardware to a drain or vent problem, which is a different repair entirely. A running toilet you can’t stop is worth fixing fast: the water waste alone usually costs more per month than the repair.
Frequently Asked Questions
Will a running toilet eventually stop on its own?
No. The fill valve will keep cycling until the leaking part is fixed, wasting up to 200+ gallons a day. It usually gets worse as the flapper or valve seal keeps degrading.
Why does my toilet run every few minutes?
Intermittent running (sometimes called ghost flushing) is almost always a slow flapper leak. The tank loses water gradually, and the fill valve tops it off every 20–40 minutes. Replace the flapper.
Can a running toilet increase my water bill?
Yes — significantly. Even a moderate leak wastes thousands of gallons a month. Utilities in the Tampa Bay area bill for both water and sewer volume, so the waste is charged twice.
How much does a plumber charge to fix a running toilet?
Simple flapper or fill-valve repairs are typically a modest flat-rate service call. Call Llona Plumbing at (813) 477-1870 for an exact quote — we answer 24/7.
Why does my toilet run with a button flush?
Dual-flush (button) toilets use a seal cartridge instead of a flapper. Mineral buildup on the cartridge seal is the usual cause — remove the cartridge, clean the seal, and replace it if worn.
Toilet Still Running? We Answer 24/7
Llona Plumbing is a licensed, bonded, and insured plumbing company (State License #CFC1431902) based in Tampa and serving homeowners across the Tampa Bay area — including Tampa, St. Petersburg, Clearwater, Temple Terrace, New Port Richey, and communities throughout Hillsborough, Pinellas, Pasco, and Hernando counties. If your toilet keeps running after these fixes — or you’d rather have it handled right the first time — call (813) 477-1870 for same-day toilet repair. We answer the phone 24 hours a day, 7 days a week — you talk to a real person, and a licensed plumber gets dispatched, not a call center promise.
