I'm not sure if this has been posted before or even if it's appropriate or not but I thought it was quite brilliant (please delete if it isn't appropriate.

Save-a-flush

Almost a third of the water we use at home is flushed down our toilets.

Fitting a Hippo device in the average cistern will save up to 3 litres of water with every flush. If one toilet is flushed ten times a day, this would equate to a water saving of 30 litres per day, enough water for a five-minute shower!