How do I check for leaks in my toilet cistern?

Most modern toilet cisterns overflow into the toilet bowl, rather than through an overflow pipe through the outer wall of your home. Leaks of this type are not always easy to spot as the water dribbles away down the back of the pan and could be wasting thousands of litres of water every year (and if you have a water meter, this will be costing you money too).

If you do have a problem with your cistern, you may be able to hear the faint sound of water as it trickles into the bowl, or a faint hissing sound as the cistern is constantly refilling. Another way to check for leaks is to dry the back of the toilet bowl before placing a piece of dry toilet paper on it. You’ll soon see the toilet paper get wet if water is trickling down into the toilet from the cistern. If you spot this is happening, you’ll then need to contact a plumber to fix the problem.

We have an easy to read guide to help you check your water usage (PDF 153 KB opens in a new window). This will help you spot sneaky leaks in your home, including how to do a simple leak test.