Part G Consultation Blog - John Slaughter

September 24, 2025

Part G Consultation - John Slaughter, External Affairs Director, Water Neutrality Group Lead (Future Homes Hub).

It is always said that patience is a virtue, and having experienced a number of false dawns on an expected announcement it is good to see the Government at last consulting on the revision of Part G of the Building Regulations.


While we have been waiting for the consultation in the last year and a half it has become ever clearer that water supply is not something we can take for granted. England does not have enough water to meet future demand sustainably unless the nation takes steps to use water more efficiently.


Alongside planned investment in new reservoirs and supply infrastructure, a major effort is needed to reduce per capita water demand if we are to avoid a prospective 5 billion litres per day water supply shortfall by the 2050s. Water scarcity is already constraining new build housing in some areas and if we are to meet the Government’s housing targets new homes will need to be more water efficient as part of a wider strategy for demand management.

The Part G consultation should be seen in this context and it is telling that it looks not just at a proposed immediate change in the Building Regulations, but also in an allied call for evidence seeks views on possible further improvements in water efficiency standards in the future.


The main elements of the consultation proposals - at Review of Water Efficiency Standards in the Building Regulations 2010 - Defra - Citizen Space - are:


  • To require a mandatory minimum water efficiency standard of 105 Litres Per Person Per Day (LPPPD), with an optional technical standard of 100 LPPPD in seriously water stressed areas, once a change in the Regulations takes effect in 2026.
  • The revision of the water calculator methodology and a proposed new set of maximum water flow limits for fittings if developers choose to meet the Regulations using the fittings-based option (details in a draft Approved Document included as an appendix to the consultation).
  • Implementation of new Part G Regulations in 2026, with a transition period of 6 months.
  • A review after the introduction and initial assessment of the Mandatory Water Efficiency Label (MWEL) scheme for fittings to consider possible alignment between MWEL and Part G.


Outside the main consultation options, views are also sought on whether a possible alternative metric to LPPPD for Part G might be considered and whether there are any Part G compliance issues.

The headline proposal to increase water efficiency standards for new build homes next year to 105, or in seriously water stressed areas, 100, LPPPD mirror the recommendations the Hub made in its 2024 “Water Ready” report which, at Government’s request, advised Defra on what we thought would be practical for advancing water efficiency in new build.


The consultation does not, however, make any proposals relating to the circumstances (or the level of standard) in which local areas may seek to set more ambitious water efficiency standards than the optional technical standard in Part G, as has been the case in a number of locations. The consultation’s background information simply references the 2023 Written Ministerial Statement that in areas of serious water stress, where water scarcity is inhibiting the adoption of local plans or the granting of planning permission for homes, it is encouraged that local planning authorities work with the Environment Agency and delivery partners to agree standards tighter than the optional technical standard in Part G. This does therefore leave the overall picture on standards subject to a lack of clarity and certainty.


On other matters, the Water Ready report also called for revision of the water calculator and proposed that Part G moved to a fittings-based approach, setting out a range of “contender specifications” for how particular levels of possible future water efficiency standards might be achieved. So, it is welcome that these issues are raised in the consultation.


The consultation makes several references to the work and findings of the Water Ready report and is accompanied by a call for evidence which seeks views on issues beyond an immediate change in Part G requirements in 2026, including:


  • Whether wider reform of Part G should be pursued
  • The possible further tightening of both the mandatory (to 100 or 95 LPPPD) and the optional technical (to 90, 85 or 80 LPPPD) Part G standards in the future
  • Whether in future water reuse systems should be required under Part G and, if so, what the issues and enablers would be.


The spirit of the call for evidence echoes Water Ready’s recommendation for the Government to adopt a practical longer-term timeline or roadmap for increasing water efficiency standards. However, the Government has not proposed any specific timetable at this stage or indicated a preference for the level of standards in any further change to Part G. That is the ground to be debated and considered under the call for evidence.


The Government’s interest in views on whether water reuse should be required under Part G is a recognition of both the Hub’s work and that of others, which indicates that achieving progressively more ambitious water efficiency standards beyond those envisaged for the 2026, change in Part G will be likely to require water reuse as part of the answer. The question of whether it would be helpful in future to specify water reuse as part of a regulatory requirement does, however, requires proper consideration.


Overall, the consultation and call for evidence is a comparatively slim document by the standards of Government consultations. This is welcomed and will help focus discussion and submissions on the core issues. The core issues are nevertheless significant and we are keen to understand members’ views and potential issues on these.


The consultation period lasts for 12 weeks until 16 December and we encourage members to respond.


We will be organising a webinar and a dedicated meeting on the proposals and look forward to engaging with you.




John Slaughter

External Affairs Director


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