Water saved by using a 'cistern displacement device' in your loo
Around a third of all the fresh, drinkable water in our homes is used just for flushing the lavatory. Older style toilets can use over 12 litres of water per flush, whereas the average modern one will still use around 8 or 9 litres. Going for a newer dual-flush model can use as little as 4 litres. Installing a device such as a hippo, save-a-flush or frog can save up to 3 litres per flush, adding up to an annual saving of over 5000 litres per household.
Carbon Saved
The carbon footprint of unheated tap water is relatively small, around 0.0003kg per litre. However over time and multiplied by millions of households, the savings can be quite significant. There are 45 million toilets in the UK, using 2 billion litres of water every day, and only around a tenth of these are water-efficient models using 6 litres of water or less. The average toilet uses around 9 litres of water per flush and 1.64 kg CO2 would be saved per year by fitting it with a hippo. Collectively in the UK this could save around 600 million litres of water a day, and over 65 million kg (or 65,000 tonnes) of CO2 each year.
Water-saving devices on the market
Cistern Displacement Devices
It's important to check if your toilet needs a reduced flush. If the water tank capacity is 6 litres or less (printed inside your tank), or you have a dual-flush toilet, it is already water-efficient and you won't need a water displacement device.
Hippo The Water Saver
The Hippo opens up into a box which sits beneath the cistern float and fills with water. When the toilet is flushed the amount which remains within the Hippo is the volume of water saved. Hippos should only be used for tanks of 9 litres or more. Have a look at these FAQs
to check its suitability.
Freddie the Frog
The frog takes up room in the cistern that would otherwise be taken up with water, saving a litre with each flush.
Save-A-Flush
The Save-A-Flush is a bag filled with crystals that absorbs water and expands in the cistern, saving a litre with each flush.
Toilet Tank Bank
A hot-water bottle shaped bag that you fill with water and place inside your cistern, saving up to 2 litres per flush.
Water-saving toilets
Dual-flush toilets are more efficient than single flush systems, and use push buttons rather than handles. They allow a main flush (long flush) of between 4 to 6 litres, with a smaller flush (short flush) button that uses around 2 litres.
- Galerie Flushwise
is an ultra-low volume dual system that uses 4 litres per long flush and 2.6 litres per short flush, and has been awarded a Waterwise Watermarque
for efficiency. Normal dual flush toilets are required to use no more than 6 litres per long flush, and 4 litres per short flush.
- SanLamere Caroma Profile 5 Integrated Toilet Suite and Hand basin
is a 4.5/3 litre dual system, with an integrated hand basin on top which recycles the water used in handwashing to flush the toilet.
- Savings on tap
profiles other ultra-low volume systems in the UK.
- Watersense have a listing of high efficiency toilets (HETS) in the US.
Other useful info
Waterwise
Waterwise has more information on water-efficient products
Waterless composting toilets
Waterless composting toilets, as the name suggests, use no water at all, and surprisingly look like normal toilets from the outside. For more information see:
Separett: http://separett.webb211.it-norr.com/
Envirolet: http://www.envirolet.com/wt.html
Rotaloo: http://www.rotaloo.co.uk/
For a guide see: http://compostingtoilet.org/compost_toilets_explained/index.php;
Greywater use
The Ecoplay system uses greywater from baths and showers to flush the toilet, after filtering and cleansing it. To avoid becoming stale the water is drained automatically if it is not used after 24 hours, or in the event of power failure.
Footnotes
