Water Efficiency Calculations
Water Efficiency Calculations are a mandatory requirement under Part G of the UK Building Regulations, demonstrating that new dwellings meet the prescribed limits for internal water use. These calculations show building control that your design achieves the required performance standard
Compliant Design for Sustainable Water Use
At Stanley Sustainability, we provide Water Efficiency Calculations to help your development meet the requirements of Approved Document G of the Building Regulations. These calculations demonstrate that your building’s design achieves the mandated water usage targets — typically no more than 125 litres per person per day.
Whether you're working on a single dwelling or a multi-unit scheme, our assessments ensure your plumbing specifications, fittings, and flow rates are fully compliant and optimised for sustainability.
What We Deliver
🚿 Detailed Water Usage Calculations – Based on flow rates, flush volumes, and usage assumptions
🏠 Fixture & Fitting Review – Assessment of taps, showers, WCs, appliances, and water-saving technologies
📄 Document G Compliance Report – Ready for submission to Building Control or planning authorities
🌍 Sustainability Guidance – Recommendations to reduce water consumption and improve environmental performance
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Why It Matters
Water efficiency is a key part of sustainable building design — and a legal requirement under Building Regulations. Our reports help you:
✅ Avoid delays in approval or sign-off
✅ Ensure accurate specification of compliant fittings
✅ Support planning applications with robust technical evidence
✅ Contribute to long-term environmental goals
Why Stanley Sustainability?
We make compliance simple, accurate, and cost-effective. By working with your design team early, we help you:
💧 Select the right fittings without overspending
💧 Avoid costly redesigns or substitutions
💧 Meet water targets while enhancing sustainability credentials
Let’s make your building water-wise — and regulation-ready.