Planning a new build or renovation? Need to comply with Part G of the Building Regulations? At Armeec, we check your plumbing fittings and water-saving measures to ensure your property hits its usage targets, helping you pass planning quickly and easily across the UK.
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A Water Efficiency Calculation is a mandatory legal requirement under Part G of the Building Regulations for all new build homes and certain conversions. It ensures that the daily water use of the property stays within strict legal limits.
Typically, the nationwide target is set at a maximum of 125 litres per person per day (which includes a 5-litre allowance for outdoor use). However, in regions where water scarcity is a concern—such as London, Birmingham, and Liverpool—local planning authorities frequently impose stricter, optional targets of 110 litres or even 90 litres per person per day.
It’s critical to get your water efficiency calculations done early in the project—ideally during the design stage—to avoid expensive retrofitting.
Commissioning calculations upfront allows flexibility. We can guide your layout and fixture selection before anything is physically installed on-site.
Ensure that the exact models of taps, showers, and appliances you are about to buy meet the necessary efficiency flow rates required to pass.
If your local council in London or Manchester demands strict 110L targets, early calculation is the only way to strategically hit those goals without blowing your budget.
To comply with Building Regulations Part G across London, Birmingham, Liverpool, and nationwide, it is essential to consider the flow rates and capacities of every water-drawing fixture in your development.
Our assessors utilize the government's official Water Efficiency Calculator methodology to process the following data points from your proposed building specification:
We log the flush volume (in litres) for both settings on dual-flush toilets. Reducing this to a 4/2.6L split is a massive saving.
The flow rate of your taps is measured in litres per minute (l/min). Using aerators or flow restrictors drastically cuts waste here.
The flow rate of a showerhead (l/min) heavily dictates your overall score, as daily showers account for a vast portion of household usage.
Baths are assessed based on their capacity to the overflow (measured in litres). Deep, oversized tubs make hitting the 110L target incredibly difficult.
Rated in litres per place setting. Specifying highly efficient 'A-rated' appliances is critical for tighter planning targets.
Water use is measured in litres per kilogram of dry clothes. Again, standardizing efficient appliances across a development ensures compliance.
If your development is undergoing a broader sustainability assessment, hitting strict water consumption targets (like 105L or 80L per person) unlocks highly valuable Wat 01 credits within the BREEAM framework, elevating your property's overall sustainability certification.
If your initial specifications fail to meet the required 125L or 110L targets, Armeec doesn't just hand you a failure notice. We provide immediate consultancy to solve the problem. Common interventions include:
We ensure seamless Part G compliance for developers across the UK.
Our energy consultants are deeply versed in Building Regulations Part G. We deliver precise reports that satisfy the strictest planning conditions nationwide.
We don't just calculate; we strategize. If your fixtures fail to meet the target, we guide you toward the cheapest interventions (like aerators) to guarantee a pass.
We handle SAP calculations, EPCs, and Water Efficiency together. Bundling these services is faster, highly cohesive, and more affordable for developers.
Everything you need to know about satisfying Part G and local council water requirements.
Don’t risk your Building Control sign-off due to poor water planning. Get in touch with Armeec today for expert, fast Water Efficiency Calculations.