Building Regulations Water Efficiency Review

The Challenge

An investigation of 80 properties across Wales in 2022/23 found that none met the requirements of the fittings-based approach, requiring the use of a calculation method instead. The calculated Per Capita Consumption (PCC) averaged 135 l/p/d—well above the required 110 l/p/d—meaning no properties were fully compliant.

Enforcement of Part G2 regulations falls under Building Control bodies, yet responses from developers and regulators showed inconsistent awareness and enforcement. Most relied on design calculations rather than verifying actual water usage on-site. Additionally, a review of over 50,000 properties built between 2015 and 2022 revealed that the expected reduction in water use following the 2018 regulation update was not fully realised, raising concerns about its effectiveness.

Without stronger enforcement and more accurate compliance methods, new homes continue to exceed the intended water efficiency targets, impacting long-term water resource management in Wales.

The Solution 

The study assessed compliance with Part G2 of the Building Regulations, which sets limits on water consumption in new dwellings. A comprehensive review of Building Regulation Part G2 and its enforcement is essential to ensure real-world compliance. 
Key recommendations include:

• On-site assessments: Physical inspections of flow rates and fittings should supplement design calculations to provide an accurate measure of actual water use.
• Revised compliance methods: Theoretical models alone are not enough—compliance should reflect real-world water consumption patterns.
• Stronger enforcement: A clearer, more effective enforcement framework is needed, considering which organisation should oversee compliance.
• Future-proofing water efficiency standards: If tighter regulations, such as reducing PCC limits to 100 l/p/d, are introduced without improved enforcement, the impact on actual water use will be minimal. A more robust approach is required to support sustainable housing and water management in the UK.

The Outcome 

The recommendations made by WRc's technical experts will contribute to long-term water efficiency goals, supporting both sustainability and resource management in new housing developments across Wales and the UK.