Receive all the latest industry news to your inbox in our newsletter Sign up
New build residential house new bathroom

Water Efficiency Calculations (Part G)

A Water Efficiency Calculation is required on residential dwellings to assess flow rates and water use of white goods. We provide a clear report showing how your new dwelling complies with the Building Regulation targets and if it doesn’t, we’ll include our recommendations for improvement.

How can Energist help

As part of Building Regulations in England and Wales, new homes must be designed to use no more than 110 or 125 liters of water per person, per day (depending on your exact location).

There is a mandatory requirement to complete a Water Efficiency Calculation to assess flow rates and water use of white goods in our homes. It is best to complete this calculation early on, so you don’t find your fixtures and fittings aren’t compliant after they have been installed.

We provide a clear report showing how your new dwelling complies with the targets and any recommendations needed if it doesn’t comply.

Request a quote Tel: +44 (0)8458 386 387

Dalton Barratt

Energy and Sustainability Specialist


Dalton Barratt

Energy and Sustainability Specialist

Why choose Energist?

  • With our fast-track service, you’ll receive the completed Water Calculations in just 7 working days.
  • In some locations you will have stricter water efficiency targets to meet because of planning requirements. Our team can produce an Energy Strategy to include these lower water use targets.
  • We can tailor our Water Calculations to also meet the strict requirements of the Code For Sustainable Homes. With 13 years’ experience in this field we get the results you need to achieve the required credits.

Complete solutions from Energist

Water Efficiency Calculations are one of a host of services that Energist’s Technical Team can help you with. You may also need:

  • For residential dwellings, a SAP Calculation is required to show energy efficiency compliance.
  • For planning applications made before 2015, Code for Sustainable Homes may still be required as part of legacy planning conditions.
  • Many Local Authorities request an Energy Statement to encourage developers to be more environmentally friendly.
  • “Energist took my drawings and notes and produced As-Built SAP results and water usage calculations for building control. The drawings had changed from original design and so a bit more time was required for the assessor to read through my notes and make the necessary adjustments.

    Very good customer service, helpful from start to finish and I was able to speak with the individuals undertaking the work to ensure my requirements were met.”

    Jack Piccaver,