At Green Norwood Day way back in June, we held a contest to see who could come closest to guessing how much money you could save each year by using a water butt to collect rainwater for your garden.

Because Thames Water charges customers for both the clean water they use and the wastewater they produce, 210 litres of tap water, roughly the capacity of a standard water butt, costs just under 85p.

We estimated that a water butt could be filled and used around 50 times over the course of a year. That works out at a saving of approximately £42 a year.

So, as well as reducing your use of clean drinking water and helping to ease pressure on the sewage system, a water butt could potentially save enough money to pay for another one within the first year.

We had guesses ranging from £25 all the way up to £840. And the winner was... Laura from Knolly’s Road, with a guess of £50 a year.

Congratulations Laura!