Rainwater Harvesting

Rainwater harvesting means simply collecting rainwater from the roof using the existing guttering and drainage system then storing the water for reuse. Rainwater harvesting systems will reduce the amount of water required from the main supply and will also reduce the amount of water run-off during storms. With water prices rising in the UK and more homes being metered, people are now realising the benefits of harvesting rainwater and using water more sustainably.

This rainwater harvesting can save a considerable amount of money every year on water bills while also reducing demands on the mains water supply. Rainwater harvesting makes a lot of sense in commercial applications where you can save thousands of pounds every year, but even in domestic situations decent savings are on offer.

There are two main types of rainwater harvesting systems, direct systems and indirect systems. Direct rainwater harvesting systems collect rainwater and then send it directly to the point of use using a backup connection from the mains cold water supply feeding into the rainwater harvesting tank. This means the tank will be refilled from the main supply if required ensuring a constant supply of water as long as electricity is available for the pumps.

Indirect rainfall harvesting systems (a.k.a. gravity or boosted systems) use a second smaller tank which is fed from the mains water supply. This can be used as a header tank at a high level which means that even if no is available the water supply will continue to run using gravity. The outlet in this type of system can also be boosted using an electric pump if greater pressure is required.

Many people in the UK when they first hear about rainwater harvesting are less than impressed, no doubt due to the fact that it seems to rain a lot in the UK and water is plentiful. However there are good reasons to install rainwater harvesting systems even in the UK seems to bring at least half the year! Everybody should be aware that freshwater that can be utilised for drinking is a finite resource around the world, so the efficient use of water is extremely importance. Many people also feel that rainwater is safer than water from the domestic mains supply is mains water has to be treated with a variety of chemicals to eliminate bacteria.

During the winter in the UK when there is often heavy rainfall, rainwater harvesting can help to reduce the impact of flooding as the existing drainage systems can often struggle to cope with the sheer amount of water during heavy storms. In addition during the summer when rainfall is scarce, if hosepipe bans are enforced, stored rainwater can still be used which is hugely beneficial for keen gardeners and for those with well manicured lawns.

The simplest rainwater harvesting system is of course a simple water butt, a large plastic container connected to the drainpipe on your guttering. This simple and cheap method is only really suitable for those harvesting rainwater for use in the garden or for car washing etc. installing proper gravity or pump fed system which is connected to your taps, is a bit more complicated and more expensive. The average cost of a domestic rainwater harvesting system is around £2500 supply only, but to have it professionally installed could cost an additional £2000 to £3000 depending on the size of tank required. The higher the water capacity the greater the cost of the system, for example, 3000L system may cost from around £2000, whereas a 5000L system could start from £3000. Underground storage tanks can also be more expensive due to the excavation costs.