What to Do About Leaky Loos

Andrew Tucker, Water Efficiency Manager at Thames Water
What better time to talk about leaky loos than World Toilet Day (19 November)? WaterSafe asked Andrew Tucker, Water Efficiency Manager at Thames Water to highlight how even a tiny trickle could be wasting around 400 litres a day – equal to five daily baths!


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.

What’s a leaky loo?

A ‘leaky loo’ usually refers to clean water leaking from your cistern down 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. Leaky loos are easy to miss, so it’s no wonder around 5% of all households and a third of businesses have one.

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. Water sector research shows that the average leaky loo loses around 400 litres a day, equivalent to five full bathtubs, or an average family’s total daily water use – doubling their bill if they’re metered. Every day we find leaky loos that are wasting over 8,000 litres a day!

So, what’s the cause?

Leaky loos are usually caused by a faulty flush-valve or fill-valve inside your tank – predominantly on dual-flush WCs. It can happen with any WC brand and type, but most leaky loos are the result of a failure in valve seals. These failures can happen on old and new WCs.

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 wipe the back of the pan dry with toilet paper.
  • Place a new, dry piece of toilet paper at 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 losing 400 litres a day will completely wet the toilet paper sheet immediately.

How do I fix my leaky loo?

Using an approved plumber is usually the safest and surest way of getting the job done correctly. Any product you or your plumber installs must be compliant with the water fittings regulations and be compatible with your toilet suite.

Fixing the Big Picture!

Water companies and Waterwise are working with WC manufacturers right now to find a leaky loo solution. Better designs, better materials, better awareness. We’re working to engineer this problem out of existence.


To find a qualified, approved plumber near you, click here.

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