Water Efficiency Calculations

Water Efficiency Calculations

Water efficiency calculations are required for all new build dwellings in order to comply with Part G of the Building Regulations, which covers sanitation and hot water safety.

Water Efficiency Calculations are undertaken to measure the flow rate from sanitary appliances including, taps, showers and also water used by 'white good' appliances.

Elmhurst Energy Consultancy can undertake these calculations to ensure compliance with Building Regulations, without the need for a site visit.

What are the current water efficiency standards?

Part G of the Building Regulations sets out certain criteria for the water efficiency of properties. Current guidelines demand a whole building standard of 125 litres per person per day, along with an allowance of 5 litres per day for outdoor water use. 

There are some circumstances where a property must meet an optional requirement of 110 litres per person per day, usually as a condition of planning permission. 

There are different standards for properties built with public money compared to those in the private sector, with the former required to meet tighter efficiency standards. 

Do I need a water efficiency calculation?

If you are building a new home, you must ensure it complies with current water efficiency standards laid out in Part G of the Building Regulations. It is therefore highly advisable that you complete a water efficiency calculation for your property. 

How do I arrange a calculation?

The first step of arranging a test is to speak to one of our advisers. After getting an understanding of your property/ extension/ project they will be able to advise you on how best to proceed. 

The calculation is desk-based and is conducted using a government-approved methodology for water efficiency calculations. 

Call us now on

01455 883 259

 and discuss your project with us, there’s no obligation and we’re happy to advise you.

Or why not complete our 'Get a quote' form



Related Links

Design Stage SAP Calculations > As-Built SAP Calculations  >


Get a quote

Please provide a few details below and we'll get back to you as quickly as possible


Elmhurst Energy Services Ltd. 16, St Johns Business Park, Lutterworth, Leicestershire, LE17 4HB

© Elmhurst Energy Services Ltd 2022. All rights reserved. Elmhurst Energy Services Limited is registered in England, Company Number: 06087105