Water Usage Calculations
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Part G of the Building Regulations
This section of the building regulations is mainly concerned with water efficiency requirements. It requires all new homes and converted properties to meet new water efficiency requirements to reduce the occupants water usage within the dwelling.
Failure to comply with the target water use figure will adversely affect the SAP rating of a newly created dwelling.
A guide to target water efficiency of fittings
Maximum Consumption of Water Fittings:
- W/C: 6/4 ltr dual flush or 4.5 ltr single flush
- Shower: 10 l/min
- Bath Capacity: 185l
- Basin Taps: 6 l/min
- Kitchen Taps: 8 l/min
- Dishwasher: 1.25 l/place setting
- Washing Machine: 8.17 l/kg
Water Reduction Strategy
Some larger sites require a full water reduction strategy as part of the planning process. This is a more detailed report demonstrating the water efficiency measures to be utilised on a site wide basis.
We, at SEES, use our BRE approved Part G water efficiency calculation tools to demonstrate compliance. Not only can we provide all the necessary documentation for your local Building Control officer, but we are also able to provide suitable cost-effective recommendations to achieve the target water consumption even after the property has been completed.
The advice of Natural England is that:
“For every new development, total water use after the development must be equal to or less than the total water-use in the region before the new development.”
Development proposals that would lead to a material increase in water demand will need to demonstrate ‘water neutrality’. This means that there would be no increase in water consumption, demonstrated by a combination of water efficiency, water recycling and offsetting measures. This should be demonstrated in a water budget, showing the baseline and proposed water consumption and mitigation measures proposed. This must be submitted as part of the planning application.
