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How to Fix a Leaking Toilet Cistern

Last Updated Apr 11, 2011 · Written by

Toilet Cisterns|How To

A leaking toilet cistern is not only annoying, it wastes a lot of water and it can really drive up you water bills.  If you’ve got a leak, it needs to be fixed sooner rather than later. Here are our tips for fixing a leaking toilet cistern.

Leaking Toilets – When to Fix and When to Call a Pro

If your toilet cistern is leaking, there are a few simple fixes that you can try before you go to the expense of calling a plumber.  Of course, if you’re not confident in your DIY abilities, call a plumber the first time around, or you could be up for more money due to the plumber having to fix your mistakes!  As well, if the below steps do not fix your leak, don’t try any other DIY fixes – call a plumber straight away.  Remember that in some states it is actually illegal to do any plumbing work at all, so you should find this out before beginning your repair.

Steps to Take to Fix a Leaking Toilet

Most often, a leaking toilet cistern occurs because you need to replace the washer in your cistern.  To do this, you’ll need a screwdriver, a pair of pliers and a new washer. Start by turning off the tap the feeds water to the toilet.  Take the lid off the toilet and then flush the loo.  There should be no water re-entering the bowl.  Look for the outlet valve (you should see it in the middle when you look down).  To replace the washers, undo the nuts under the cistern.  You can undo the bottom one with your fingers, but you’ll need multi grip pliers for the one at the top.  Lift out the outlet valve and replace the washers inside it.  Simply pop the washers out with the screwdriver and fit new ones in.  You can then put the outlet valve back into the toilet.  Turn the water supply to the toilet back on; let the cistern refill and then flush to see if this has solved your problem. 

If this doesn’t fix the problem, you’ll need to get a new cistern outlet kit and fit it to the toilet.  As outlined before, remove the kit from the toilet and take it to your hardware store or plumbing supply store along with the make and model of your toilet. They will be able to provide you with a new cistern outlet kit which you can then install.  Simply fit it in place in the tank and do up the nuts – remember the bottom one is finger tight and the top one must be tightened with pliers.  Again, turn the water supply on to the toilet and let the cistern refill before flushing.

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