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Check your toilet for leaks

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A leaky toilet can waste upwards of 22,000 gallons of water every year, so don't let that faulty toilet go another day!

How to check your toilet for leaks

Stop wasting water by regularly checking your toilets for leaks—both obvious and silent types, that is.

Obvious leaks

We all know that annoying sound of a toilet running hours after you flushed. And we're equally familiar with the tedious job of jiggling the toilet handle to get it to stop running. These problems are not to be ignored! They're serious water wasters and should be fixed as soon as possible so you can put a stop to water and money waste. So, if your toilet exhibits any of these symptoms, call a plumber or put on your work hat.

  • You have to jiggle the flush handle to get the toilet to stop running.
  • You hear sounds coming from a toilet that is not being used.
  • You have to hold the handle down to completely empty the tank.

Silent leaks

Other toilet leaks are not so obvious. Try the following methods to uncover leaks you might not otherwise see or hear, but which can be tremendous water-wasters over time.

The dye test:

  1. Dry all exterior surfaces of the toilet (around the base of the bowl, the underside of the tank, and the floor around the base).
  2. Remove the tank lid and flush the toilet.
  3. Add about a teaspoon of food coloring or dye tablets to the tank.
  4. Do not flush the toilet.
  5. After an hour, check the bowl for traces of the dye.
  6. If you see color, your toilet is leaking and one of the mechanisms inside needs to be replaced or adjusted.

The paper towel test:

  1. Follow the four three steps of the dye test, but this time add dye or food coloring to the bowl as well.
  2. After a wait period, run a dry paper towel around the exterior of all parts of the toilet. If any trace of color appears on the paper towel, you know you have a leak.
    • If color appears when you wipe around the base, the wax ring needs to be replaced.
    • Color detected on the underside of the tank could mean either a leaking fill valve, bolt gasket, or spud washer.

Water meter test for slower leaks:

  1. Make sure that all water fixtures are turned off.
  2. Note the numbers shown on your water meter at this point.
  3. Do not use any water for 30 minutes. Come back to read the meter again.
  4. Compare the readings. If they match, you're leak free. If the readings are different, turn off your toilets and repeat steps 1-3.
  5. If the readings match after your toilets have been shut off, one or more of your toilets leaks.

DIY toilet repairs

Check out's useful guide for identifying which part of your toilet needs replacing and how to do it yourself. San Jose's Environmental Services Department also has an extremely useful publication about toilet repairs. Print a copy and use it as reference. Or pursue Toiletology 101's online course focusing on toilet leaks and repairs.

Find it! Leak detection dye tablets

Here's some common options for checking toilet leaks, But before you make a purchase, check first to see if your municipal water provides these to customers free of charge.

Checking your toilet for leaks helps you go green because…

  • It conserves water.
  • It conserves energy.

The American Water Works Association estimates that toilets account for 45 percent of total water use in a typical household and that 20 percent of them leak.[1] Each leaky toilet can waste over 22,000 gallons of water per year.[2] If a toilet is allowed to leak continually, it may lead to structural damage to the floor around the base of the toilet, as well as possible damage to the ceiling of the room below.

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