How Do You Fix A Toilet That Keeps Running?
QUICK ANSWER
A constantly running toilet is almost always one of three problems: a worn flapper (most common), a faulty fill valve, or a float set too high. Lift the tank lid and check each component. Most fixes take under an hour and cost less than 20 dollars in parts.
A toilet that keeps running wastes hundreds of gallons of water per day and adds significantly to the water bill. The fix is almost always a quick part replacement inside the tank. The trick is identifying which of the three common parts is the culprit. Here is how to diagnose the problem and the right repair for each.
What causes a toilet to keep running?
Fluidmaster, the largest US toilet fill valve manufacturer, identifies three primary causes: a leaking flapper at the bottom of the tank, a malfunctioning fill valve at the top, or a float adjusted too high so water continually drains into the overflow tube. Lift the tank lid and watch the water as the tank refills after a flush. If water keeps trickling into the bowl after refill is complete, it is the flapper. If water keeps pouring into the overflow tube, it is the fill valve or float.
How do you fix a flapper issue?
The flapper is the rubber valve at the bottom of the tank that lifts when you flush. Over time the rubber hardens, warps, or accumulates mineral deposits so it no longer seals against the flush valve seat. To test, drop a few drops of food coloring into the tank and wait 15 minutes without flushing. If color appears in the bowl, the flapper is leaking. Replace with a matching flapper (Korky and Fluidmaster brands are universal-fit). Costs about 5 to 10 dollars and takes 10 minutes.
How do you fix a fill valve issue?
The fill valve is the vertical assembly on the left side of the tank that controls water refill after a flush. If water keeps flowing into the overflow tube (the open vertical pipe in the middle of the tank), the fill valve is either set too high or not shutting off properly. First try adjusting the float: lower it so the tank fills to about an inch below the overflow tube top. If adjustment does not fix it, replace the fill valve (universal Fluidmaster 400A is the standard, around 12 dollars, 30-minute install).
When should you replace parts versus just adjusting them?
Adjust first if the parts look intact. If the flapper is visibly warped, hardened, or has black residue, replace it. If the fill valve is over 10 years old, replace it even if you can adjust it back to working since the diaphragm is probably brittle. Replace both fill valve and flapper if the toilet is over 15 years old and the parts are original. Universal repair kits include both for around 25 dollars and are the safest long-term fix for older toilets.
A running toilet is almost always a flapper, fill valve, or float adjustment issue. Use the food coloring test to identify a flapper leak. Replace any worn rubber parts with universal Fluidmaster or Korky components. The whole job takes under an hour and costs under 25 dollars. Catching this early saves hundreds of gallons of water and a significant water bill increase.
More Plumbing & Bathroom Questions
Mystery Question?
Mystery Question?
Mystery Question?