shutterstock_96680230A toilet leak that goes unfixed leads to water wastage and a costly water bill. Some toilet leaks are easy to detect, while other types can be harder to identify and repair. These are common causes of toilet leaks and some basic steps you can take to repair them.

Take a meter reading

A basic test for toilet leaks is to check the meter. Wait until bedtime or a time when you do not expect  the household to use any water-based appliances, then turn off all taps and take a water-meter reading. In the morning, take another meter reading before using any appliances or flushing the toilet.

Toilet tank leaks

Slow leaks in toilet tanks tend to be silent or quiet, making them harder to detect. By using food colouring, however, you can quickly determine whether there is a slow leak in your toilet.

Remove the lid of your toilet tank or cistern and apply five or six drops of food colouring to the water. Use as much food colouring as is required for a discernable change in the colour of the water. Wait 30 minutes or more, and check the toilet bowl – but it’s important to make sure that no one flushes the toilet in the interim. If the water in your toilet bowl is tinted, then the tank is leaking water into the bowl and you may need to follow one of the following steps to repair the issue.

External toilet leaks

If you are concerned about an external leak from your toilet tank, place a few pieces of paper around and behind the toilet bowl. Check the paper 10 or 20 minutes after flushing the toilet. If the paper is damp, there is an external toilet leak.

Check the float and inlet valve

A faulty float or inlet valve could lead to toilet tank leaks. The float should rise with the level of the water, and the inlet valve shuts off the water when it reaches a certain level inside the toilet tank. When these are faulty, the tank keeps filling with water until it runs into the overflow tube, which leads directly into the bowl. This causes water wastage.

A simple test can tell you if the float and inlet valve are working properly. Flush the toilet with the lid of the tank removed. As the water fills the bowl, lift the rod connected to the float. If the water stops rising, the inlet valve is working as it should be and the problem is probably a faulty float. In this case you can adjust the level of the float by using the screw at the top of the ballcock for the float, or replace the float itself.

If the tank does not stop filling, there may be issues with the ballcock. If so, you may need to have the whole assembly replaced by a plumber.

Change tank bolts and spud washer

Some leaks are caused by faulty tank bolts and/or spud washers. To replace these items, you will need to drain the tank completely, remove the toilet tank, and install a new spud washer and tank bolts. This can be a trickier job, so it might be a good idea to have a professional plumber install the bolts and washer on your behalf.

If the above corrective steps do not fix the problem, there may be other issues causing the leak. In this case, have a plumber inspect your toilet.