Water efficiency targets for new dwellings in the UK have become more fragmented following a change to Welsh building regulations in November. There are now several different targets to achieve, depending on your location.
Approved Document Part G (Wales) 2018 now requires new houses to have fixtures and fittings installed which are designed to use no more than 110 litres of water per person per day. The previous version required a target of 125.
The calculation for showing compliance considers the flow rates of taps and showers, the flush size of toilets, bathtubs, washing machines and dishwashers.
The regulations, which were introduced in 2010, do not impose actual water use limits on new homes, it instead encourages the use of efficient fittings to reduce unnecessary water waste.
Currently (end of 2018), the regional water use targets are:
In Wales, new homes should be designed to use no more than 110 litres.
It is the same target in London, where a planning requirement pushes all developments to achieve 110.
In the rest of England, Part G has a two-tiered requirement, depending on your local authority. If your development is in an area which is prone to water shortages (mainly big cities and the east) you may be required to achieve 110 litres, but if the council hasn’t specified, 125 litres would be expected.
In Scotland, there is no overall target to aim for. Technical Handbook Section 3 requires new homes to be fitted with toilets that flush at a maximum of 4.5 litres, and basin taps have a maximum flow rate of six litres per minute.
New dwellings created out of change of use development would usually be expected to apply with the above targets.