Freerain, based at Collingham on the Nottinghamshire border with Lincolnshire, installs the system in new and existing houses.

It collects rainwater from the roof and stores it underground, keeping excess water out of the drainage system.

According to a spokesperson for the firm the recycling system provides enough water for up to half a household's total needs.

Simon Hepple, Sales Engineer, said: "They end up being a sales tool.

"We've had two or three clients who have bought properties purely for the reason that we install these as part of the standard specification."