Source-backed values from Approved Document G for new dwellings and fixed baths.
Approved Document G is useful for source-backed value recall because it gives separate anchors for water efficiency and hot-water safety.
For new dwellings, the normal water-efficiency limit is 125 litres per person per day. Where the optional requirement applies, the value is 110 litres per person per day. For bath hot-water safety, Part G also sets a 48 °C maximum delivered temperature for water supplied to a fixed bath.
Keep these as Building Regulations revision facts. They do not replace the full document, local building-control advice, manufacturer instructions or practical assessment requirements.