Part G water use calculations

ISO 14001 and water supply regulation

From us you’ll get straightforward advice about how to comply with water use limits under part G of Building Regulations.

And after we’ve modelled your project you’ll get a notice of water efficiency compliance report that you can send to your building control body.

All new dwellings need to comply with part.G. This sets a design limit on the water use from the dwelling at 125 litres per person per day.

Efficient use of water is likely to become more important in the future as changing weather patterns and increased demand raise the cost of water supply.

Additional credits are also available under Code for Sustainable Homes for developers who can show that the design can reach higher standards of water efficiency.  Where dwellings are designed to achieve 80 litres per person per day.

Which parts of the system are modelled?

  • Tap flow rates
  • Shower flow rates
  • Flushing capacities of WCs
  • The water use per place setting of dishwashers
  • The water use per dry kg of washing at washing machines
  • Greywater specifications
  • Rainwater harvesting potential