Over the past few years, Part G Building Regulations have changed for all new homes, extensions and conversions and property owners are now legally required to comply with new water efficiency targets to ensure a truly environmentally friendly building project.

At Falcon Energy, we're always up to date with such changes and are your number one choice when it comes to staying on top of Part G Water Calculations for homes and properties in the UK.

What are Part G Water Calculations?

As of 2010, Building Control and local councils in England and Wales can legally request water calculations to prove that a new build, conversion or extension is water efficient. These rules mean all new homes must not use more than 125 litres of potable water (water that is safe to drink) per person per day to ensure stringent energy efficiency.

This means that building developers will have to consider the types of:

  • Taps
  • Toilets
  • Showers
  • Baths
  • Other water-producing appliances they'll be fitting

This ensures that everything that is fitted conforms with these guidelines.

Why are Part G Water Calculations important?

Now more than ever, it's important for new builds, conversions or extensions to be environmentally friendly and as energy efficient as possible. With a rise in energy wastage in recent years, local councils and the government are encouraging property owners and homeowners to play their part in energy efficiency and water output is a key factor.

Part G Water Calculations ensure that any building project is complying with these regulations and wasting as little energy as possible.

Those who don’t comply with these water efficiency measures will see their SAP calculations for the dwelling negatively impacted. This can cause problems when selling the home, as a property needs to have passed the SAP calculations in order to be viable for sale.

What impacts the water efficiency of a property?

There are a range of factors that need to be considered that can impact the consumption of water at a property. These include:

  • Flow rates of any showers and taps at the property
  • The capacity of any baths
  • The flush of the toilet
  • The dishwasher consumption per place setting
  • The washing machine consumption per load
  • If there are any rain harvesting technologies installed
  • If there are any water softeners installed and how efficient they are

Why Falcon Energy for Part G Water Calculations?

Our team at Falcon Energy are highly experienced at conducting thorough Part G Water Calculations and ensuring optimal results to tight deadlines and budgets. There's a range of solutions available including rainwater harvesting systems to capture and reuse rainwater or reduced flow taps and showers. Whatever the plans for the build, we'll help find the best solution for you.

Our formal calculations will be in line with Building Control regulations and government outlines and we'll offer the best advice possible to move your project forward with minimum disruption. To work with us, call Falcon Energy now on 01403 253439 or email info@falconenergy.co.uk. We're here to help.


Frequently Asked Questions

What are Part G Water Calculations?

The Code for Sustainable Homes and Building Regulations require Part G Water Calculations to assess the water performance of a property in terms of estimated water consumption per person per day.

This is measured in accordance with water performance targets stated in the Building Regulations Part G, and highlights ‘water consumption shall be no greater than 125 litres/person/day’. It is calculated by reviewing the flow rates of water features in a property.

Calculations are made to correspond to the ‘Water Efficiency Calculator for New Dwellings’, which is available here to view.


When do you need a Part G water calculation?

Part G water calculations are required for all new build properties and for existing properties that are being converted and altered.

If new builds are required to meet a certain level on the Code for Sustainable Homes, this will affect how water use and features should be planned at the design stage.

Levels 1 and 2 have a maximum of 125 litres/person/day, levels 3 and 4 have a maximum of 105 litres/person/day and levels 5 and 6 have a maximum of 80 litres/person/day.

Calculations should be made at the design stage and again on completion.


How can water consumption be reduced?

A number of measures can be inbuilt or added to a property to reduce water consumption and make the property more sustainable. These include reduced flow taps and showers and solutions where rainwater is harvested and reused.


High or Low-Pressure System?

The Water Efficiency Calculator for New Dwellings states that flow rates must be taken at:

  • a dynamic pressure of 3±0.2 bar for high pressure or
  • at a dynamic pressure of 0.1±0.02 bar for low-pressure systems.

If your property has a cold water tank, you’re likely to have a low-pressure system that is gravity fed. Combination boilers and unvented systems highlight the likelihood of a high pressure system. If you’re unsure, our team can assess the pressure when the calculations are done.