Water efficiency and the Building Regulations

[edit] In Brief

Part G of The Building Regulations 2010 covers Sanitation, hot water safety and water efficiency. Section G2 of these Regulations has a requirement for a water consumption below 125 litres per person per day, with an optional requirement of 110 litres per person per day, as measured in either case in accordance with a methodology approved by the Secretary of State. Proposals announced in September 2025 would reduce the upper limit by 20 litres and the optional lower limit by 10 litres, thus revising the minimum Water Efficiency Standard in new houses through fittings from 125 l/p/d to 105 l/p/d, and the optional technical standard from 110 l/p/d to 100 l/p/d. The consultation which launched on 26 September and ends 16 December, 2025 includes a call for evidence on water reuse systems in new developments, to enable even greater water efficiency.

[edit] What Part G2 of the Building Regulations currently says?

The current Part G2 of the 2010 Buildings Regulations states:

"Water efficiency. G2. Reasonable provision must be made by the installation of fittings and fixed appliances that use water efficiently for the prevention of undue consumption of water.

Water efficiency of new dwellings. 36.— (1) The potential consumption of wholesome water by persons occupying a new dwelling must not exceed the requirement in paragraph (2). (2) The requirement referred to in paragraph (1) is either— (a) 125 litres per person per day; or (b) in a case to which paragraph (3) applies, the optional requirement of 110 litres per person per day, as measured in either case in accordance with a methodology approved by the Secretary of State. (3) This paragraph applies where the planning permission under which the building work is carried out— (a) specifies the optional requirement in paragraph (2)(b); and (b) makes it a condition that that requirement must be complied with. (4) In this Part, “new dwelling” does not include a dwelling that is formed by a material change of use of a building within the meaning of regulation 5(g).

Wholesome water consumption calculation. 37.—(1) Where regulation 36 applies, the person carrying out the work must give the local authority a notice which specifies— (a) which of the requirements in regulation 36(2)(a) or (b) applies to the dwelling; and (b) the potential consumption of wholesome water per person per day in relation to the completed dwelling."

[edit] Announcement

On 23 September the Government announced its planned changes as water saving plans to reduce bills and unblock new homes.

Simple water-saving measures could save families in new homes over £100 a year on bills, while supporting a wave of new housing across Britain – delivering on the Plan for Change. The government’s new efficiency rules will tackle water shortage bottlenecks and unblock stalled developments in areas of water scarcity helping to deliver the pledge of building 1.5million homes by 2030.

A consultation launched today will propose small changes to Building Regulations that could see new homes fitted with water-saving features such as aerated taps and shower heads, and dual flush toilets. The change to the design standard will make new build housing more water efficient, equivalent to 20 litres per person per day. Analysis has shown this could save £111 a year on energy and water bills in new homes.

The small measures will also help the environment by reducing the amount that needs to be taken from rivers, lakes, and delicate chalk streams for public supply. The 12-week consultation looks to amend the current Building Regulations 2010 Part G2, which are insufficient to meet the parallel challenges of housing delivery and water conservation.

A reduction of 20 litres per person per day could see an additional 1,000 new homes unlocked for every 5,250 homes built. This is particularly helpful in areas like Cambridge and north Sussex where planning has previously been blocked because water demand outstripped supply.

The measures will support the government’s commitment to reduce water usage in England by 20% per person per day by 2038. It also puts us on track to use just 110 litres per head of the population by 2050. Future innovations, such as using harvested rainwater to flush home toilets, are also being considered in a call to evidence that is running alongside the consultation.

England has seen seven consecutive months of below-average rainfall, with five areas in drought and more expected to follow soon despite the recent rain. Climate change and increased water demand means the nation needs to become more efficient with the water it has.

Defra has worked closely with the Ministry for Housing, Communities and Local Government (MHCLG) to develop the consultation and ensure it supports housebuilding goals.

[edit] Reactions to the plans

Environment Secretary, Emma Reynolds, said:

"We are getting Britain building faster, and a key element to growth is smarter water consumption. Removing the water shortage barriers that have stalled development for too long will mean unlocking thousands of new homes while saving families money."

"Not only will this make customer bills cheaper; it will protect the environment and unlock thousands of new homes as part of our Plan for Change."

Dr. Tom Dollard, Chair, Good Homes Alliance welcomed the consultation saying:

"Our membership is facing real challenges in delivering new homes due to a lack of water capacity in their areas. If we are to meet the Government housing delivery targets and unlock economic growth then we must start building more ‘water smart’ homes and neighbourhoods."

"We would like to see a refreshed Part G that is aligned to the water neutrality hierarchy, and a fittings-based approach combined with a water labelling scheme that would deliver water efficient homes at scale across the UK. We encourage all stakeholders from across industry to respond to this important consultation.”

Ed Lockhart, CEO of Future Homes Hub:

"Water shortages are already constraining housing growth and the water supply shortfall at national and regional levels will widen without concerted action."

"To sustain delivery of new homes at the levels required for everyone to have a decent home, homes need to become progressively more water efficient, alongside large scale investment in water infrastructure and demand management in other sectors."

"That is why the Future Homes Hub proposed a water efficiency roadmap for the new homes sector in the 2024 Water Ready report. We therefore welcome the Government consulting on proposed efficiency measures and look forward to working with the Government to ensure water efficiency can be implemented affordably at scale whilst delivering on customer expectations.”

[edit] Guidance on water efficiency

[edit] GHA. Water Efficiency and Reuse in Housing: Design Guide for a Changing Climate.

In July 2025, the Good Homes Alliance (GHA), in partnership with industry leaders and supported by the Enabling WaterSmart Communities project and the UK Water Efficiency Collaborative Fund, launched a new publication - Water Efficiency and Reuse in Housing: Design Guide for a Changing Climate.

Developed for architects, developers, planners, and housing associations, the guide, authored and edited by architect Pollard Thomas Edwards (PTE), provides case studies, best practice, and industry insight to respond to the urgent need for ‘water-smart’ homes due to mounting water stress in the UK.

[edit] Waterwise

'Advice on water efficient new homes for England'

[edit] NHBC

'Water efficiency in new homes An introductory guide for housebuilders' Revised July 2010

[edit] Related articles on Designing Buildings

• Approved document G.
• Approved documents.
• Building Regulations.
• Drains.
• Hot water.
• Water.
• Types of water.
• Passive water efficiency measures.
• Water efficiency – The next big sustainability issue?.
• Delivering water efficiency in commercial buildings: A guide for facilities managers
• Water-use efficiency
• Wholesome water