A leaking toilet flush may seem trivial, but you should know that it can cost you a lot of money. To avoid unpleasant surprises on your water bill, it’s important to know what’s causing the leak and what effective solutions there are.
What causes a leaking flush?
When it comes to plumbing, one of the most common problems we come across concerns the flushing mechanism. If there’s a leak every time you flush, here are the causes:
The supply valve or the flush valve is loose;
The screws and nuts that connect the cistern to the other parts of your toilet are also loose;
Cracks in the cistern;
The flush valve doesn’t close properly.
Flush leakage: how do you recognise the problem?
When a toilet flush leaks, litres of water are wasted. But it’s easy to spot a water leak. If you see water dripping steadily from your toilet cistern into the bowl, it’s probably a water leak. A dripping noise inside the tank could also alert you to a water leak.
How can I check my toilet?
Investigating a water leak in your toilet is very simple:
Flush the toilet and wait 30 minutes;
Wipe the inside of the bowl with toilet paper;
Place another piece of dry toilet paper around the edge of the bowl;
Wait at least 3 hours without using the toilet;
If after this time the paper is wet, you have a water leak.
How do you repair a small flush leak depending on the cause?
How to repair your leaking flush depends, of course, on the cause of the problem. Start by determining the source of the leak.
If the flapper is the cause of the leak
The flapper is the part of the toilet that lifts up and releases the tank valve to let the water flow into the bowl when you flush. If it’s not positioned correctly, it can let the water run continuously. Pour a few drops of food colouring into your cistern and wait a few minutes. If coloured water flows into the bowl without you having to flush, the valve may be incorrectly fitted. Here’s what to do in this case:
Close the stopcock to stop the water supply;
Empty the cistern by flushing several times;
Remove the toilet cistern cover and blot up any water remaining at the bottom of the cistern;
Check the quality of your flapper. If the rubber is no longer supple and malleable, replace it. To do this, remove it from the chain on the flush handle and fit the new one by attaching it to the chain;
Open the tap to refill the cistern;
If, after checking, your valve is correctly positioned and working as it should, the leak is coming from somewhere else.
If the seal is the source of the leak
To check whether your leak is due to a faulty seal, the task is a little more complicated, as you have to completely detach the cistern from the other toilet components. This is a fairly complex operation, so it’s best to call in a professional plumber. But if you want to do it yourself, get help to lift the tank, and carefully follow the steps below:
Turn off the water supply tap;
Flush the toilet until there is no more water in the tank;
Unscrew the nuts that hold the retaining bolts in place with a spanner. To make it easier, hold the top of the bolt with a screwdriver;
Unscrew the locknut that connects the tank to the water supply pipe;
Detach the tank from the toilet;
Take a look at the condition of the rubber seal. If it’s hard or cracked, it needs replacing. Remove it and put the new one in its place;
Replace the cistern on the bowl and refit the retaining bolts;
Tighten the nuts carefully;
Turn on the tap and fill your cistern.
If the water supply pipe is the cause of the leak
Your water leak may also be coming from outside the tank. Check the supply pipe that connects your toilet to the plumbing network. Water may be leaking from the fittings or from a hole between them.
Avoid over-tightening the nuts, as they can easily be damaged;
To prevent further damage, first tighten them by hand, then use your spanner to turn them a further quarter-turn;
If the leak is coming from a hole between the fittings on the water supply pipe, there’s nothing you can do yourself! Contact a plumbing expert to carry out the repairs.
For your information
Before repairing your water leak, it is advisable, for safety reasons, to wear rubber gloves to avoid contact with waste water. It’s also a good idea to keep towels on hand to catch any toilet water that escapes while your water tank is being repaired.