Service Overview

A water Part G report for Building Regulations deals with the sanitation, hot water safety and water efficiency requirements. Under Building Regulations, it is mandatory to comply with Requirement G2 – Water Efficiency of Part G.

The requirement states that “Reasonable provision must be made by the installation of fittings and fixed appliances that use water efficiently for the prevention of undue consumption of water”. Under Requirement G2 newly erected dwellings or dwellings formed by a material change of use (e.g. office-to-resi conversion) must demonstrate that the average potable water consumption does exceed 125 litres/person/day.

However, Local Councils can set more onerous targets as part of their policies or planning conditions. Additionally, under the Code for Sustainable Homes the following consumptions should not be exceeded:

  • Level 1 & 2 – 120 litres/person/day
  • Level 3 or 4 – 105 litres/person/day
  • Level 5 & 6 – 80 litres/person/day
To achieve lower consumption rates, it is sometimes required to incorporate flow restrictors, rainwater harvesting or water recycling. Where the latter options are required, it should be discussed with the design team at early stages to avoid mediatory work and expense as well as risk of non-compliance.

The calculation for potable water consumption considers the specification of

  • Basin taps
  • Showers
  • Baths
  • WCs
  • Urinals
  • Kitchen taps
  • Dishwashers
  • Washing Machines & Washer Dryers
  • Water softener
  • Waste disposal systems

At the Syntegra Group, our Energy Certification team can provide guidance on targeted flow rates and consumption levels for different fitting as well as review and comment on specification to ensure that the requirement can be achieved in an appropriate strategy for the site.


Our expert team of planning specialists, sustainability consultants and Chartered Engineers are here to help.

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