BREEAM Wat 01 — water consumption

Wat 01 rewards reduced potable water consumption from sanitary fittings, assessed with BRE's water calculator against a baseline. It is one of the most reliably achievable credit sets in BREEAM because it is decided almost entirely by specification — provided the specification is locked before procurement substitutes fittings.

What earns the credits

• Efficient WCs, urinals, taps and showers, specified by measured flow and flush rates rather than by product marketing.
• Consistency between the specification, the calculator inputs and what is actually installed.
• Where appropriate, rainwater or greywater reuse contributing to the assessed demand.

Why projects lose Wat 01 credits

Almost always substitution: a compliant fitting is value-engineered out and replaced with one whose flow rate has not been checked against the calculator. The fix is procedural — flag the water-critical fittings on the specification, and check the installed schedule against the calculator before post-construction evidence is compiled.

The rest of the Water category

Wat 01 sits alongside water monitoring, Wat 03 leak detection and efficient equipment credits. Our full approach to the category is on BREEAM water credits, and water-intensive buildings are covered on BREEAM for data centres.

Want the Water category credits secured?

Send your sanitaryware specification and we will tell you which Wat credits are already earned and what would change to gain more.

Book a BREEAM assessment or request a fixed-fee quote — we reply the same working day with the scheme, timeline and fee for your project.

Frequently Asked Questions

What is BREEAM Wat 01?

The water consumption credit set, assessed with BRE's water calculator, which rewards reduced potable water use from sanitary fittings against a baseline.

How do I evidence Wat 01?

With the completed water calculator, the fittings specification and flow and flush rate data, and confirmation at post-construction stage that the installed fittings match.

Does rainwater harvesting help Wat 01?

It can contribute where the system serves the assessed demand and is properly evidenced, but efficient fittings are usually the cheaper route to the same credits.

Related BREEAM pages

• BREEAM guidance hub — every scheme, category and rating explained
• BREEAM assessment cost — what drives your fee
• BREEAM pre-assessment — score forecast before design freeze
• How to achieve BREEAM Excellent
• BREEAM glossary — schemes, categories and credit references