Water Efficiency Calculations

Water Efficiency Calculations are a methodology for assessing water efficiency in new dwellings in support of The Code for Sustainable Homes and the Building Regulations. If you are building a new home, you will need a water efficiency calculation to calculate the water consumption of the dwelling. This is calculated using several assumptions outlined in the guidance and is calculated in litres per person per day.

Approved Part G of the building regulations sets the standard of 125 litres of water consumption per person per day for domestic buildings. This compromises water usage of 120 litres per person per day plus an allowance of 5 litres per person per day for outdoor water usage.

It takes into account the flow rate of terminal fittings such as taps, showers, toilets, bathtub sizes and the water used by ‘white goods’ such as dishwashers and washing machines. Using wastewater or rainwater systems can significantly improve water efficiency.

At Air Tightness Solutions, we measure the water usage of your home.  We will undertake the water efficiency calculation required for new dwellings to comply with Part G of the Building Regulations 2014, for England and Wales. We also provide consultation for alternative methods of water usage and sustainability methods if your home fails to meet the requirements.