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Making sure new buildings use water efficiently has been on the Government’s agenda for several years now, and has been a part of Building Regulations in England and Wales since 2010. Now, with the recent conclusion of the Housing Standards Review, Approved Document Part G is changing; and although some developers may find themselves with tougher targets to meet, the general opinion is the new rules around water efficiency are easier to follow.

The new Approved Document goes live on October 1st 2015, however, local planning authorities have been told to adopt the water use targets with immediate effect, and to replace any local planning conditions with the guidance in the new Part G. This means councils can no longer ask for their own unique water use targets, and can’t insist on developers designing to meet a particular level of the category WAT1 of the Code for Sustainable Homes. It’s worth noting on this point that these changes will not affect planning applications which were approved prior to March 30th 2015… the council-specific planning conditions will still apply in these cases.

So, the Part G water efficiency target in 2010 said that new buildings should be designed to use no more than 125 litres of water per person per day. There is a calculation which takes into account flow rates from taps, showers, baths and toilets. It also considers white goods, greywater and rainwater harvesting systems.

In the 2015 version, this rule still applies. The 125 litre target is still in place. However, councils have the power to enforce an ‘optional requirement’; these areas must meet 110 litres per person per day. Local authorities which previously insisted on Code for Sustainable Homes compliance, had mandatory planning conditions asking for less than 117 litres, or where a council can prove they are in an area where water reserves are low can all adopt the 110 litre target.

For all other councils, the 125 target will be enforced. As CSH is coming to an end, the additional water restriction requirements of the Code no longer apply. These are the only two options available to councils going forward. So, instead of one national and upteen regional targets for water use, there are now just two targets - 125 or 110 – throughout England and Wales. To prove compliance, just as before, you can have a water use calculator completed. However, under the new regulations you have the choice to opt out of completing this step, providing you agree to install fixtures and fittings which apply with the ‘Maximum fittings consumption’ table. In summary (125 litres target): Table2.1 In summary (110 litres target): table 2.2 If you agree to each one of these points, you will not need to have a full calculation completed. If just one of your fittings exceeds the above limits, or if you are installing greywater or rainwater, or if you are installing a water softener or waste disposal unit, then you must have a full calculation completed. The rules of Part G apply to all new domestic and most non-domestic buildings in England and Wales. Developers should follow the above flow rates of new fixtures and fittings in renovation and extension projects also. If you require more information about the changes to the water efficiency targets, or need a calculation completed for your next project, please contact us 08458 386 387 or alternatively email us at

Jon Ponting

Author: Jon Ponting

This article was published by Jon Ponting on 12.08.2015.