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The Water Efficiency Calculations for New Dwellings

Complete EPC – Water Calculations Assessors For Your Property

Part G water calculations are based on “The Water Efficiency Calculator for New Dwellings” – The Government’s national calculation methodology.

In water usage calculation we require the use of water consumption figures from manufacturers product details.

Over the next 20 years, demand for water is set to increase substantially. This will be driven by population growth coupled with an ambitious programme of development on one hand, and increasing per capita water consumption on the other.

Yet there is likely to be less water available – climate change is forecast to make it drier and the EU’s environmental protection legislation, combined with the general direction of government policy is likely to lead to tighter controls on abstraction.

The overall picture is one of ever increasing demand for an ever scarcer resource, and less water will need to go further.

The economy is heavily dependent on water for agriculture, industry, tourism and recreation. Water shortages during drought have a deleterious effect on the internationally significant rivers, wetlands and wildlife and we must ensure that this is not exacerbated by the effects of abstraction.

Part G of the Building Regulations and the Code for Sustainable Homes.

Water Calculations CertificateThe Government is driving a sustainable development programme that mandates improved water efficiency in the built environment. The Code for Sustainable Homes was introduced in 2007 and Part G of the Building Regulations now includes water efficiency for the first time.

In addition, improved water efficiency in new development will be backed-up through the planning system, as the Government allows the planning system to mandate water efficiency targets in excess of the Building Regulations where there is demonstrable local need.

What are water efficiency calculations?

Water efficiency calculations predict water consumption in line with Part G of The Building Regulations. You need these calculations for all new builds, as well as some conversions. The water efficiency of a property is becoming increasingly important to make homes more sustainable.

What is a water efficiency certificate?

A Water Efficiency Certificate is a document that states a particular property is certified as water efficient.

How much water does a pumped shower use?

With a low-flow showerhead, you can expect to use about two gallons of water each minute, equating to 10 gallons over a 5-minute period. If a standard showerhead is fit, the shower will likely emit around an extra half gallon of water per minute, so a 5-minute shower will use in the region of 12.5 gallons.
water usage chart

What can Affect a Dwellings Water Usage?

Please see below a list of installations and their factors that can affect the water consumption of your dwelling.

  • The Flushing Capacity of Toilets / WCs (single or dual flush)
  • The Flow Rate of Taps (Bathroom and Kitchen / Utility Areas)
  • The Litres per kg of Dry Load for Washing Machines
  • The Capacity to Overflow of Baths
    The Flow Rate of Showers
  • The Litres per Place Setting of Dishwashers
  • The use of Waste Disposal or Water Softeners.

If any Rain Water or Grey Water harvesting is installed and used on site this can also positively affect your overall total water consumption. An allowance for external water usage of 5 litres per person per day is also accounted for in the calculations.

If you have a new project/development, or are converting an existing development for a new purpose such as commercial into dwellings, it is likely that you will require water calculations performed to attain building control signoff.

If you need advice on how your property can achieve Building Regulations Part G for its water calculations please contact us now. Our friendly and professional team are here to help you.

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