What is a Part G Calculation and Do I Need One?

The Part G water calculation looks at water supply, drainage, and efficiency in residential dwellings. It refers to a key section of the UK Building Regulations.

What is the Part G Water Calculation?

Part G regulations serve as a crucial framework for ensuring public health & safety and environmental sustainability in residential buildings. The regulations cover various aspects related to water supply, water efficiency, drainage, and sanitation in buildings. Complying with Part G regulations is not only a legal requirement but is also a means to safeguard public health, conserve water resources, and uphold high building standards.

Do I Need a Part G Assessment?

All new builds, extensions, and conversions must demonstrate compliance with Part G by undergoing a Part G assessment.  Part G water calculations are used to assess the water performance of a property in terms of estimated water consumption, which cannot exceed more than 125L of potable water per person per day. 

What does the Part G Water Calculation involve?

The Part G calculation involves evaluating the design plans and assessing factors outlined in the table below:

Why is it important?

Part G regulations align with the broader goal of environmental sustainability. By promoting water efficiency and conservation, they help reduce strain on natural ecosystems and lower energy requirements for water treatment and distribution. 

Aside from being a legal requirement, Part G assessments also impact your SAP calculations. By considering part G regulations and conducting part G assessments, you can prevent your SAP score from taking a significant hit.

What next?

Undertaking the water calculation is a simple part of the building compliance process, yet it is an important one. If it is overlooked, assumed default data will be entered into the SAP calculation, which will have a negative impact on the final EPC score awarded to the property.

If you need support with regulatory compliance, building sustainability, or planning, get in touch with our friendly team.