A running toilet is one of the most common household problems — and one of the most annoying. That constant sound of water running can waste up to 200 gallons of water per day and add serious money to your water bill.
The good news? You can fix it yourself in under 30 minutes with no plumbing experience.
What Causes a Running Toilet?
Most running toilets are caused by one of three things: a worn flapper, a faulty fill valve, or a float that’s set too high. All of these are cheap and easy to fix.
What You’ll Need
Before you start, grab these items: A replacement flapper (costs around $5–10 on Amazon), an adjustable wrench, rubber gloves, and a towel.
Step 1: Check the Flapper
Remove the lid from the toilet tank. Look at the rubber flapper at the bottom — if it looks warped, cracked, or doesn’t sit flat, it needs replacing. This is the most common cause of a running toilet.
Step 2: Turn Off the Water
Find the shut-off valve behind the toilet near the floor. Turn it clockwise until the water stops.
Step 3: Replace the Flapper
Flush the toilet to empty the tank. Unhook the old flapper from the two side pegs and disconnect the chain from the flush handle. Snap the new flapper onto the pegs and reconnect the chain — leave about half an inch of slack.
Step 4: Check the Fill Valve
Turn the water back on and let the tank fill. If the water keeps running after the tank is full, your fill valve may need replacing. Fill valve replacement kits cost around $10–15 and come with simple instructions.
Step 5: Adjust the Float
The float controls the water level. If it’s set too high, water spills into the overflow tube and the toilet keeps running. Adjust the float arm downward until the water stops about an inch below the overflow tube.
You’re Done
Turn the water back on, flush once, and listen. If the running has stopped — you just saved yourself a $150 plumber bill.
If your toilet is still running after these steps, the issue is likely the fill valve. Replacing it takes about 20 minutes and the parts cost under $15 at any hardware store.