Water Efficiency
Calculations

All new homes in England must meet strict water usage requirements under Part G of the Building Regulations 2010. For a new dwelling in England, the standard requirement is that potential wholesome-water consumption must not exceed 125 litres per person per day. A 110-litre-per-person-per-day optional requirement applies where the planning permission specifies it and makes compliance with that requirement a condition.

Water efficiency calculations estimate potential daily water consumption per person, based on the number and type of fittings and appliances specified for the dwelling. Toilets, showers, baths, taps, dishwashers and washing machines are included in the Approved Document G methodology, where relevant. The calculation uses the relevant fitting characteristics and manufacturer-declared appliance values. Where the fittings approach is used, the applicable maximum consumption values in Approved Document G are used as an alternative to completing the calculator.

The person carrying out the work must provide the required water-consumption information to the local authority in accordance with the Building Regulations. A calculation report may also form part of the project’s building-control evidence, depending on the building-control process and project requirements. Keeping this information accurate from an early stage can help avoid discrepancies, late changes or the need to revisit the specification.

If full product specifications are not yet chosen, we can provide a product and fixtures schedule designed to support compliance with the applicable Part G requirement. For developers, contractors and architects, this makes the process straightforward and reduces risk.

At enevo, we supply fast, accurate assessments and practical recommendations so your project stays compliant, efficient, and on track.