Toilet Repair & Installation
Stop a toilet from running, rocking or clogging, or set a new one.
Homeowner tips
Running Toilet Fix: Easy Steps for Westminster, CO Homes
Put dye in the tank and wait ten minutes. If color reaches the bowl, the flapper is leaking and a new one will likely stop the running.
By the Westminster Plumbing Co. team ·
Do the dye test
Drop a dye tablet or a few drops of food coloring into the tank. Do not flush. Wait at least ten minutes, then look at the bowl. Color in the bowl means the flapper is not sealing.
The city recommends the same test on its water leaks page, since a silent toilet leak can waste a lot of water.
Replace the flapper
Shut off the supply, flush to empty the tank and unhook the old flapper from the overflow tube. Take it to the store to match the style. Hook on the new one, adjust the chain so there is a little slack, and turn the water back on.
Hard water makes rubber stiffen, so a flapper may last only a few years. Replace it sooner if you see scale.
Fill valve problems
If the water level rises to the overflow tube and keeps running, the fill valve is not shutting off. Adjust the float, or replace the fill valve. Modern valves are inexpensive and install with a wrench.
A hissing sound after a flush is another sign. It may be a worn seal in the valve.
What the sound tells you
The noise and the behavior point to the failing part.
| What you notice | Likely part | Fix |
|---|---|---|
| Runs for a few seconds every so often | The flapper | Replace the flapper |
| Hissing after a flush | The fill valve | Adjust or replace the valve |
| Water at the overflow tube | The float set too high | Lower the float |
| Sweat on the outside of the tank | Condensation | Insulate the tank or lower humidity |
Float and level
The float controls when the fill valve stops. If it is set too high, water spills into the overflow tube. Lower it so the water stops about an inch below the tube.
A chain that is too tight holds the flapper open. A chain that is too long can get under the flapper.
When it is not the tank
Water on the outside of the tank is condensation. It occurs on humid days, when the cold tank meets warm air. An insulated liner or a lower humidity fixes it.
A leak at the base is a different problem. It needs a new wax ring.
When to call a plumber
Call if the repair does not stop the running, if the toilet is old and parts are scarce or if the supply valve is stuck. A plumber can replace the whole fill and flush assembly or the toilet.
If you also see a high water bill, check the meter and consider a leak test in the rest of the house.
Parts you will need
A universal flapper, a fill valve kit and a small bottle of food coloring cover most repairs. Take the old flapper to the store to match its size, since two-inch and three-inch openings use different parts. Many hardware stores sell all of this for a modest price.
Have a sponge, a bucket and a small adjustable wrench ready. The tank holds only a few gallons, but a spilled tank on a bathroom floor is an easy mess to avoid.
Step by step with a fill valve
Turn off the supply valve behind the toilet and flush to empty the tank. Disconnect the supply line and the nut under the tank, then lift out the old valve. Place the new one so the top sits about an inch above the overflow tube, and tighten the nut by hand plus a quarter turn.
Reconnect the supply line, turn the water on slowly and watch for drips at every joint. Raise or lower the float until the refill stops roughly one inch under the rim of the overflow tube. Flush a few times to confirm that the tank refills and shuts off.
When the fix does not hold
If the toilet keeps running after new parts, look at the flush valve seat where the flapper rests. Mineral scale or a rough edge can prevent a seal. A gentle scrub with a non-scratch pad often restores it.
A hairline crack in the tank or a worn seat on an old toilet may be beyond repair. At that point replacing the toilet costs about the same as chasing parts, and a new low-flow model will use less water on every flush.
Saving water and money
A running toilet can waste hundreds of gallons a day, often silently. Even a faint trickle adds up over a billing cycle, and the cost shows on both the water and sewer lines of your bill.
Replacing a flapper and a fill valve costs little and takes an afternoon. Do it as soon as you notice, and recheck the dye test a week later to be sure the seal is holding.
When a running toilet hides a bigger leak
A toilet that refills every few minutes with no one flushing is called a phantom flush. It signals a slow leak past the flapper, and the water loss can go unnoticed for months. Use the dye test to confirm it before the next bill.
If the tank stays full but water trickles in the bowl, look at the overflow tube and the fill valve height. A fill valve set too high sends water down the tube all day, which wastes just as much as a bad flapper.
A five-minute monthly check
Add a few drops of food coloring to the tank once a month and wait ten minutes without flushing. If color appears in the bowl, the flapper has started to leak. Replacing it early costs a few dollars and keeps the bill steady.
Common questions
Answers about running toilet
A lot over a day or a month, depending on the leak. The meter shows the effect.
Usually not. Most fixes involve a flapper or a fill valve and take a few minutes.
The dye test. Color in the bowl means the flapper leaks.
Only if it is cracked or the flush is poor. Parts are inexpensive.
Related services
Leak Detection
Trace a hidden leak behind a wall, under a slab or along the buried line before any wall has to be opened.
Faucet & Sink Repair
Cure dripping taps, weak streams, seized shutoff valves and leaking hose bibs.
Keep reading
Toilet won't flush: what to check
A toilet that will not flush has a short list of causes. Check the tank, the clog and the bigger line before you call.
Reasons your water bill jumped
A bill that suddenly climbs normally traces back to just a few culprits. Check the meter, the toilets and the sprinkler before you call.
Finding a hidden water leak at home
A moving meter, a damp basement wall or a bill that jumped. A handful of quick tests tells you whether you have a leak and roughly where.
Toilet still running?
Call and describe what it does. The dispatcher then matches you with a nearby contractor.