Part G Water Calculations

Regulation 17K of the Building Regulations states that all new dwellings (including those created through a material change of use) must achieve a projected water consumption of no more than 125 litres per person, per day.

The projected water consumption is to be calculated in accordance with the methodology set out in The Water Efficiency Calculator for new dwellings.

We can provide you with a copy of the calculations required for compliance with Regulation 17K. Furthermore, to ensure every dwelling achieves a pass we will advise you on the minimum acceptable efficiency for each terminal fitting.

  • FAST
    – we aim to complete every Part G water calculation within five working days.
  • COMPREHENSIVE
    – we will provide you with all the relevant documentation required for compliance with Regulation 17K of the Building Regulations. No hidden extras and no hidden charges.
  • VALUE
    – we aim for every quote to be the most competitive, with large discounts available for multi-dwelling developments.

What affects the projected water consumption of a dwelling?

Factors that affect the calculated water consumption of a dwelling include:

  • The flow rate of showers and taps;
  • The capacity of baths;
  • The flushing capacity of WCs;
  • The consumption per place setting of dishwashers;
  • The consumption per kilogram of dry load for washing machines;
  • The efficiency of water softeners (where present); and
  • Whether there is any on-site rainwater or greywater harvesting.