Toilet Repair & Installation
Cure a toilet that runs, rocks, leaks or clogs, or install a replacement.
Homeowner guide
Running Toilet in Louisville, CO: How to Fix It Fast
A toilet that runs on and on has a leak between the tank and the bowl, or a fill valve that never shuts off. Both are simple to find and cheap to fix.
By the Flatirons Express Plumbing team ·
Confirm the leak
Add food coloring to the tank, do not flush, and wait fifteen minutes. If color appears in the bowl, the flapper is leaking. If not, the problem is the fill valve or the overflow tube.
Listen too. A hiss after the tank fills means the fill valve is not closing. Water running into the overflow tube means the level is too high.
Replace the flapper
Turn off the supply, flush to empty the tank, and unhook the old flapper. Take it to the store to match the style. Install the new one, attach the chain with a small amount of slack, and turn the water on.
A chain that is too long can get caught under the flapper. One that is too short holds it open. Aim for about a half inch of slack.
Adjust or replace the fill valve
If water keeps running into the overflow tube, lower the float so the water stops about an inch below the tube. Most fill valves have an adjustment screw or clip.
A worn fill valve can be replaced with a universal kit. It takes about twenty minutes. Turn off the supply and use a towel for drips.
What to replace first
Most running toilets come down to one of three parts.
| What you notice | Likely part | Fix |
|---|---|---|
| Water trickles into the bowl | Worn flapper | Replace the flapper |
| Water runs over the overflow tube | Fill valve set too high or failing | Adjust or replace the fill valve |
| Tank refills at odd times | Slow leak past the seat | Clean or replace the seat and flapper |
| Hissing after a flush | Fill valve or supply issue | Replace the fill valve |
Check the flush valve seat
The flapper seals against a seat at the bottom of the tank. Mineral buildup or pitting stops a seal. Wipe the seat and check it with a fingertip for rough spots.
If the seat is damaged, the entire flush valve may need replacement. That is a longer job and is where a plumber may help.
The cost of ignoring it
A running toilet can waste a large volume of water in a month. Because the noise is faint, many go unnoticed until the bill arrives. Louisville's city asks residents to conserve water because its supply is limited.
Fixing it also protects against a flood if the fill valve fails altogether. Parts are inexpensive.
What a leaking flapper costs you
A flapper that does not seal lets water trickle from the tank into the bowl all day. The fill valve opens to replace it, and the cycle repeats. The loss is silent, which is why many people never notice until a bill arrives.
Because the water keeps moving, a running toilet shows up on the meter during the leak test. Add a few drops of food coloring to the tank and wait fifteen minutes without flushing. Color in the bowl proves the flapper is leaking.
Choosing the right replacement parts
Bring the old flapper to the store, or measure the opening of the flush valve. Many toilets use a two-inch flapper, but three-inch valves are common on newer models. An adjustable universal flapper is a handy option when you are not sure.
Fill valves come in a few styles, and most are adjustable in height. Look for one with a stated height range that matches your tank. Turn off the supply, flush to empty the tank, and carry a sponge for the last of the water.
Stopping the problem from returning
Mineral deposits and chlorine tablets in the tank wear rubber parts faster. Skip drop-in bowl cleaners that sit in the tank. Wipe the flapper seat gently with a cloth now and then to remove film.
Replace the flapper every few years as routine care. If you have hard water, a visible crust around the seat is common. Persistent problems in several toilets in an older house may deserve a wider look at the supply pressure and the fittings.
Reading the water meter after the fix
After replacing parts, repeat the dye test and watch the meter with everything off. A dial that holds steady confirms the repair. If the dial still turns, another toilet or a hidden leak may be involved.
Check every toilet in the house, including a rarely used guest bath. A silent leak in an unused toilet can run for months without anyone noticing, and it is one of the cheapest leaks to fix once found.
A word on older toilets
Toilets from the early low-flow years sometimes flush poorly or leak around the flush valve, and parts for a few models are hard to find. If you replace the same part twice in a year, consider a new toilet instead of more repairs.
Newer toilets flush with less water and often do a better job. Replacement is a manageable project, and toilet repair and installation explains what to expect.
Simple tools for the job
Most repairs need only an adjustable wrench, a sponge, a bucket and the new part. Take a phone photo of the tank before you start, so you can see how each piece fit together. Work with the water off and the tank empty.
Do not overtighten plastic nuts, because they crack. Hand-tight plus a small turn is normally enough. Open the supply slowly and check each connection for drips before you walk away.
When to call a plumber
Suppose the flapper and fill valve are new and the toilet keeps running anyway. Then the flush valve or the tank itself may be failing. A cracked tank lets water into the room.
Call for toilet repair if the toilet wobbles, leaks at the base or runs despite your efforts. See also leak detection if the bill stays high.
Quick answers
Running toilet questions
A slow flapper leak lets the tank drop, and the fill valve tops it up. This is called phantom flushing.
It can waste a large amount over a month. The leak is often silent.
Many last several years, but hard water and cleaners shorten that.
Not usually, but it should be fixed soon. If it overflows, close the supply valve.
Services that connect to this topic
Leak Detection
Pinpoint a concealed leak in a wall, a ceiling or the buried supply line, so only the right spot gets opened.
Bidet Installation
Fit a bidet seat, a handheld sprayer or a freestanding bidet with a proper supply line and shutoff.
Keep reading
A toilet that refuses to flush
Most flush failures are a tank problem or a clog. Check the water level, the flapper and the chain before you call.
Seven reasons a water bill climbs
A sudden jump usually has one of seven causes, from a running toilet to a sprinkler that stuck open.
Tracking down a hidden leak at home
A meter test, a toilet dye test and a walk through the basement can find most leaks before you call anyone.
Toilet still running?
Call and describe what you tried. A dispatcher can connect you with a local contractor.