• Rainwater Harvesting

    WCI design, install and maintain domestic rainwater harvesting for a variety of uses.

Rainwater harvesting generally describes the collection, filtering, storage and ultimately the re-use of rainwater that falls on the roofs of houses, garages and other man-made buildings. With a range of potential uses including garden irrigation and car washing as well as re-use for grey-water applications and drinking water, rainwater harvesting is as relevant for existing houses as it is for new builds.

Why harvest rainwater?

The demand worldwide for fresh water has tripled over the last 50 years and is increasing by 64 trillion litres a year (Aquastat – The Food and Agriculture Organization of the United Nations). Closer to home, water and sewerage bills have increased by 40% since the water companies were privatised in 1989.

Harvesting rainwater captures the free, naturally soft, water that falls on your roof and stores it for re-use later. Typical uses include:

  • Garden irrigation & washing cars (7% of domestic water usage)
  • Toilet flushing (30% of domestic water usage)
  • Clothes washing (13% of domestic water usage)
  • Personal washing (33% of domestic water usage)

How does it work?

Rainwater harvesting can be broken into 4 stages:

  1. Collection: rainwater downpipes are connected to underground pipes which deliver the rainwater to the filtration device.
  2. Filtration: filtration removes debris from the rainwater so that only clean, oxygenated water is retained. The filtration stage typically includes a coarse leaf-filter, fine sediment filter, calmed inlet and floating suction filter.
  3. Storage: storage of collected rainwater is generally below ground in purpose-built storage tanks. Storage tanks can be installed in gardens and under driveways. Above ground tanks are also possible where ground conditions or access prevent below ground storage.
  4. Delivery: a submersible pump and control system deliver clean water from the storage tank to point of use. Direct systems use the pump and a pressure vessel to deliver water directly to the point of use whereas indirect systems pump water to a header tank in your loft.


WCI is an independent designer and installer of rainwater harvesting systems. We only specify reliable systems (such as www.rainharvesting.co.uk) and components which meet your particular requirements and, as a sewage and wastewater specialist, WCI can draw on a wider range of storage tanks, pump systems and filtration systems than many specialist rainwater harvesting suppliers.


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