The Hippo claims to save you up to 3 litres of water every time you flush the toilet, by reducing the volume of your toilet’s cistern. For slimline toilets, a slightly smaller version of the Hippo can be bought, which will save up to 2 litres. There is a small carbon saving of around 0.003 kg per litre, which over time will add up, especially if all toilets are altered. For those on a water meter, it should significantly reduce your bill, as on average 30% of your water usage is via your toilet.
How does it work?
Simply open the hippo up and position it in the cistern. When the toilet is flushed, the water confined within the Hippo’s polyethylene bag is saved, although there are small holes in the Hippo to ensure the water is continually replaced so it doesn’t become stagnant.
How did it work for me?
Being on a water meter I thought it prudent to look into ways of saving water, and the Hippo is a cheap, simple option that seems to reduce my water bill. You simply open the hippo and push the corners out to create a box, and then position it underneath the ball cock (the float in the water) to save water on each flush.
I have had no problems with the device since installation, and I can notice that the amount of water being used in each flush is much less.
For those with other types of cistern, it isn’t necessarily evident when you buy it that the hippo will only work on 9 litre systems. If you have a slimline cistern, you need to buy the smaller hippo.
Overall, the hippo seems to do the job. Is it worth it? If you are on a water meter and you can’t find something else to displace the water in your cistern, this will do the job, and it will save you money as well. But could you not just fill a milk bottle and put it in the cistern, or use a brick or stone? Well, yes.