Toilets are one of the most common source of water leaks in homes. A toilet leak can waste up to 5 gallons of water every minute (7,200 gallons per day)!

If that much water were leaking from the toilet onto the floor into the bathroom, it would be very noticeable. However, most toilet leaks flow from the tank on the back of the toilet into the bowl, and then into the sewer. They may not make much, if any, noise. A toilet leak doesn't just waste water, it costs you money. Both the water that went down the toilet and the sewer treatment for that amount of water show up on your water bill.

Use Your Water Meter to Find a Toilet Leak


Checking for a Flapper Leak (video - 1:42)

  1. Take the lid off of your toilet tank.
  2. Put in a few drops of food coloring or a few dye tablets.
  3. Wait 25 - 30 minutes.
  4. Do not flush or use the toilet.
  5. Look in the bowl. If the coloring has seeped from the tank into the bowl, you have a toilet leak.

*Check the flapper. If black residue rubs off when you touch it, you need to replace it.

Other Parts to Check

  1. If the float is not adjusted properly, water can continue to fill into the tank, and drain down the overflow tube. Pull up on the float. If the water stops running, you might need to adjust the float.
  2. The fill valve / inlet valve is not set properly or has malfunctioned. This sometimes causes a hiss or a squeal when filling. Try adjusting the fill valve. You might need to replace it.
  3. Do you need to jiggle the handle to make the water stop running? You need to adjust the chain attached to the handle so that the flapper sits in the valve seat properly.

Brochure on Finding and Fixing Toilet Leaks (PDF - 1.02MB)

Learn to Repair Common Toilet Problems

Last Edited: March 11, 2020