techy stuff
a bit more detail
The Science
Water goes through many energy-heavy steps to get to your tap; including filtration, chemical treatment and pumping. Your loo, your clothes and your garden don’t need tap water.
Rainwater and treated greywater (i.e. the water from your bath, shower or washing up) use less chemicals and energy and are perfectly clean.
In the UK, each square metre of roof space will collect about 1000 litres of rainwater per year.
There are two main types of specialist water systems, rainwater harvesting and greywater recycling. Both require a separate plumbing system.
Rainwater harvesting
- Your building collects rainwater from the roof and stores it
- This water is used in WCs, for washing and in the garden
Greywater recycling
- Collect waste water from sinks, baths and showers (not the loo!)
- Clean it in a series of hidden tanks, then use this water for the same things that you use rainwater for














