Nicholas Soames:To ask the Secretary of State for Communities and Local Government if he will bring forward proposals to create a statutory requirement that all commercial and domestic new-builds should be required to harvest roof water for non-potable usage. [90208]

Andrew Stunell MP; Parliamentary Under-Secretary of State: To reduce the use of wholesome water, the 2010 changes to the building regulations introduced for the first time requirements for a calculated whole building performance standard for water use in new homes, currently set at 125 litres/person/day.

As the regulations are a functional approach, they allow the appropriate use of non-wholesome water for flushing of WCs and other non-potable uses, such as irrigation, and the approved documents that provide statutory guidance in support of the building regulations give additional advice on the use of rainwater harvesting and water from baths, basins and showers (referred to as "greywater") for non-potable uses.

This approach reflects a policy in which water efficiency measures should always be considered before rainwater harvesting or greywater systems, which, if not properly designed and installed, carry a risk of cross-connection and can be more energy and carbon intensive than mains supplies. They can also be costly and require routine maintenance in order to maintain effectiveness.

In light of the above, the Government consider that it would be inappropriate to make regulations to specifically require rainwater harvesting to be provided in all new buildings.