Cisterns that predate 1991 tend to use around nine liters of water, while later models typically use around 7.5 and those installed since 2001 tend to use six. Aside from flushing less frequently (as per the old saying “If its yellow …”), the easiest way to make savings is to put a displacement device in the cistern.
The only disadvantage of this approach is that some old-fashioned toilets don’t work as well with a displacement device in place. If you find that your flush isn’t working as effectively as it used to, try moving the displacement device to a different part of the cistern, if possible, or swapping it for something smaller.
When fitting a new toilet opt for an eco-flush model that allows you to choose a full or half setting. These are widely available, though you might want to turn to a specialist supplier for a super-efficient toilet that uses as little as four litres of water for a full flush and two for a half flush. For the really committed, you could consider a reed-bed sewage treatment set-up or even do away with a conventional toilet altogether and use a composting model.
In terms of the impact on the environment more broadly, also think about what you flush. It only takes a blockage at the sewage works for such items such as tampons and condoms to back up into our waterways and end up in rivers and on beaches.
Baths and showers
A five-minute shower typically uses around 25 liters of warm or hot water, compared to 80 liters for a bath. So there’s a good case for heeding the green cliche of taking fewer baths and more showers (as long as you don’t have a pressurized power shower, as these can use up to 120 liters a go). Other possible steps include reducing the temperature of the water or taking shorter showers, though you’ll get more gain and less pain by opting for an aerated shower head. These reduce the amount of water needed for an invigorating shower by up to 60% by mixing air with the water.
The American company Evolve has even produced a shower head designed to avoid the water and energy wasted when the water is left running to warm up. A thermostat automatically reduces the flow once the water has reached the correct temperature. When the person gets into the shower they flick a switch and the water starts flowing again.
If you’re sufficiently motivated, it’s even possible to reuse bath water for your garden. This can be done with a Drought Buster siphon pump, which runs from the bath to an outside water butt, via a window. You squeeze the device to get the flow going, and gravity should take care of the rest. As well as saving water, this can be very handy during dry spells with hosepipe bans.