Rainwater harvesting systems (RHS) – as you might expect from the name – harvest the rainwater that has fallen freely from the sky, typically onto the roof of your home. In contrast to the humble water butt, which typically captures about 200 liters of rainwater, a rainwater harvesting tank can easily filter and store up to 6,500 liters of clean water.
What’s more, while these systems have traditionally been used to water the garden, new technology means an RHS can now be plumbed into your home’s existing pipework and the rainwater used to flush toilets and wash clothes. This means that you could reduce your water consumption by as much as 40%, according to the Rainwater Harvesting Association, which – if you switch to a water meter – will lower your water bills as well.
Rain Harvesting vs. Grey Water Recycling
The amount of water you save with one of these systems is lower than the 50% savings that you can potentially get with a greywater recycling system because rainwater supply is less certain. “You will need to be able to rely on your mains water system as a backup during periods where there is little rainfall”, says Derek Hunt, from Rainharvesting Systems.
However, unlike a greywater recycling system, RHS requires little specialist maintenance and the rainwater you harvest – as it has never been used to wash food or the human body – is likely to contain far less bacteria and contaminants than greywater. This can make RHS a cheaper and more environmentally-friendly choice for many homeowners, say the proponents of these schemes.