Water Efficiency Calculations
UK Building Regulations Part G requires that installed sanitary equipment meets a high standard for water efficiency.
Minimum domestic water efficiency standards are 125 litres per person per day
Building Regulations require that new dwellings and conversions meet minimum standards for water efficiency. A maximum amount of 125 litres per person per day is the minimum standard, with local planning conditions or water suppliers often reducing this down to 110 litres per person per day.
Evidence to demonstrate the compliance of a development with this regulation is given by means of a water efficiency calculation. This calculation is based on fittings and flow rates.
Part G details a maximum fitting approach that would lead to compliance. Table 2.1 and 2.2 show approaches for 125 and 110 litres compliance respectively: