WATER EFFICIENCY CALCULATIONS

 Part G of the Building Regulations requires all new dwellings to meet strict water‑efficiency standards. 

Every new home must demonstrate that its design uses water responsibly and stays within the allowed consumption limit.

Part G calculations assess:

• Predicted daily water use per person
• Flow rates of taps, showers and appliances
• WC flush volumes
• Bath and shower capacities
• Any additional water‑saving features

The target for new dwellings is ≤ 125 litres per person per day, unless a local planning condition requires a lower limit (often 110 litres).