Showing results for 
Search instead for 
Did you mean: 

How to fix a leaky loo

Thames Water Employee

Sadly, that water trickling into your toilet bowl isn’t a cool design feature to help keep it clean!


If your loo is constantly dribbling, it’s probably leaky.  


The good news is you can get it fixed to save yourself water and money. Here’s how…


What’s a leaky loo?

A leaky loo usually refers to clean water leaking from your toilet tank into your toilet bowl. If you have one, you may notice a steady trickle of water at the back of the bowl or hear a constant dripping sound inside the tank. But sometimes, you may not notice anything at all.


Leaky loos are easy to miss, so it’s no wonder around one in 10 households and most businesses have one they haven’t fixed yet.


Why fix a leaky loo?

A little dribble may seem like nothing, but don’t be fooled. If you’re on a metered bill, a leaky loo can be really expensive. In some cases, it could more than double your water bill. Yikes!


Even if you’re not on a metered bill yet, the average leaky loo wastes as much as 400 litres of water every single day. That’s the equivalent of five full bathtubs and probably more a family of four would normally use washing, cooking, cleaning, drinking, watering your plants and flushing the loo combined.  We’ve even found leaky loos that are wasting over 8,000 litres a day!


How do I check my loos?

It’s really easy to check whether you have a leaky loo. Just:


  • Wait for 30 minutes after flushing and then wipe the back of the pan dry with toilet paper.
  • Place a new, dry sheet of toilet paper on the back of the pan. Leave it there for up to three hours without using the toilet (it might be best to do this overnight).
  • If the paper is wet or torn, you have a leaky loo. An average leaky loo of 400 litres a day will completely wet the toilet paper sheet immediately.


What’s the cause?

Leaky loos are usually caused by a faulty flush valve or fill valve inside your tank.


To check your flush valve, mark the water level inside your tank and pop back 10 minutes later. If the water level has dropped, you’ll know the flush valve is the problem.


If not, the fill valve may be responsible for the leak. If you can, look to see if any water is running into the overflow tube inside your toilet tank. If your tank takes a long time to refill or your flush isn’t as powerful as normal, that could also be a sign your fill valve isn’t working properly.


How do I fix my leaky loo?

If you’re pretty handy, you can find instructions for replacing your flush or fill valve online.  Don't forget that if you have home plumbing and drainage cover, such as HomeServe, you'll be able to give them a call. You can also find a plumber to pop out and fix the problem for you. 


If you have a smart water meter, a leaky loo could cost you as much as £300 a year. Why not book a free Smarter Home Visit from our team of experts now? As well as fixing your leaky loos for free, we can:


  • Fit free water-saving gadgets around your home 
  • Share expert advice on how to save money and energy 
  • Show you how to make the most of your smart meter
  • Give you a free benefits entitlement check and debt advice


Got more questions for us? Sign up for community now and share them in the comments below!



Water Royalty

Thanks for these tips Faye, I'll look into homeserve. My husband is a Mr. Fix It but sadly fixing leaks are not his forte.  Smiley LOLSmiley LOL

Community Manager
Community Manager

@MindTheGap Homeserve is great! I would certainly recommend it. Smiley Happy

Thames Water Employee

You're welcome @MindTheGap! I second @AkhilVyas - HomeServe can be a great option if you want a little more peace of mind. You can find out more here Smiley Happy