PART G · Water and sanitation
What is the water efficiency limit for new homes
For relevant new dwellings in England, the usual water efficiency standard is calculated consumption no greater than 125 litres per person per day. An optional 110 litre standard applies where the relevant planning condition requires it. These are design calculations, not daily rationing rules for occupants.
How is consumption assessed
The calculation uses the specified fittings and relevant appliance information under the applicable methodology. Taps, showers, toilets and baths can all affect the result.
Actual household consumption will also depend on behaviour. Passing a design calculation does not guarantee a particular water bill.
Does the lower standard apply everywhere
No. The optional requirement needs the relevant trigger. Check the planning permission and associated conditions rather than assuming the lower number applies throughout a council area or to every project.
Ask the designer to record the applicable standard and the route used to demonstrate it. Material changes of use creating dwellings can also require consideration of the water efficiency rules.
Why do product changes matter
A contractor may substitute a shower or tap during construction. If its flow rate differs, the original calculation may no longer describe the installed dwelling.
For example, replacing a specified low-flow shower with a higher-flow model should prompt a review before installation, not an explanation after completion.
What should you arrange before handover
Make sure the final specification and calculation agree. Retain manufacturers' performance information and the required notice or evidence of calculated consumption.
Water efficiency should remain practical. Choose fittings that suit the available water pressure and the intended users while meeting the applicable design requirement.
This standard does not mean an existing homeowner must replace every fitting simply because the household uses more than 125 litres per person. Identify the building work and its regulatory trigger first.