Appendix 5: Policy implementation - Water efficiency and residential


Policy DM4 requires all new, replacement or converted dwellings to be designed to have a water demand of 110 l/h/d. This is the optional building regulations standard that has been incorporated into the Local Plan.

What the Building Regulations 2010 (as amended) say…

Building Regulations 2010 (as amended)[193]

The relevant Building Regulations Approved Document are part G. Approved Document G provides guidance on the supply of water to a property, including water safety, hot water supply, sanitation and water efficiency i.e. an easily accessible water supply that doesn’t incur wastage. Approved Document G - Part G - Sanitation, hot water safety and water efficiency - Planning Portal

G2 is the specific part that relates to water efficiency.

With regards to the optional requirement, which we adopt in the Local Plan, it says:

‘The optional requirement only applies where a condition that the dwelling should meet the optional requirement is imposed as part of the process of granting planning permission.’

Calculating water use

The Approved Document G (in particular G2) refers to two approaches.

… the estimated consumption of wholesome water calculated in accordance with the methodology in the water efficiency calculator, should not exceed 110 litres/person/day’.

As an alternative to calculating the water consumption, a fittings approach that is based on the water efficiency calculator methodology may be used. Where the fittings approach is used, the water consumption of the fittings provided must not exceed the values in Table 2.2’.

Maximum fittings consumption optional requirement level

The Water Efficiency calculator is at Appendix A of Approved Document G.

Planning Applications

Since the policy requirement is tied to national standards in the Building Regulations, the process for providing the necessary information to support a planning application is relatively straightforward.

4.1 Pre application discussions

Water efficiency will be one of the policy requirements to be discussed by development management planners and developers from the earliest stages of the design and planning application process. Early consideration will reduce associated costs.

4.2 Submitting planning applications

Reference to the requirement for the housing development to comply with the regulation 36 2(b) for water efficiency, and how this will be addressed, should be incorporated in the Design and Access Statement which supports the planning application.

4.3 Assessing planning applications

For all residential development, regulation 36 2(b) for water efficiency of the Building Regulations will be applied.

4.4 Conditions

Standard water conditions will be applied to relevant planning permissions. These are to ensure that the appropriate levels for water efficiency have been achieved. The standard condition is as follows:

The development hereby approved shall be designed and built to meet the regulation 36 2(b) requirement of 110 litres/person/day water efficiency set out in part G2 of the 2015 Building Regulations for water usage. No occupation of [any of] the dwelling[s] shall take place until a Building Regulations assessment confirms that the development has been constructed in accordance with regulation 36 2(b) of part G2 of the Building Regulations for water efficiency and has been submitted to and agreed in writing by the local planning authority.

REASON: To ensure the development is constructed to an appropriate standard in accordance with Policy DM4 of the adopted Local Plan for the Broads.

4.5 Long term maintenance

It will be important that developers inform residents and other users of their developments of both the advantages of the installed water efficiency devices and systems and of any issues related to long term maintenance.

Table 3: Typical water usage and maximum consumption of water by fittings for compliance with Building Regulations


Water fitting, appliance or action

Average water use of each appliance/action

Approximate % of average household’s water use

Building Regulations maximum fittings  consumption to achieve optional requirement level of 110 litres per person per day



Power shower: 13 litres per minute

Mixer shower: 8 litres per minute

Electric shower: 5 litres per minute


8 litres per minute

Bath tap

Standard: 80 litres when the bath is ‘full’*


170 litres total holding capacity to overflow


Modern cistern: 5 litres per flush

Older: 9 litres per flush


4/2.6 litres dual flush

Bathroom basin

6 litres per minute is used with a running tap


5 litres per minute


Washing machine

Average cycle: 50 litres


8.17 litres per kg of dry load capacity used per average cycle**



Average setting: 14 litres per cycle

Eco-setting: 10 litres per cycle

16% (‘Kitchen’)

1.25 litres per place setting capacity used per average cycle**

Kitchen sink (rinsing/

hand washing)

30 litres per minute running tap wash

6 litres per minute

Washing up dishes by hand

8 litres per bowl wash



Car wash / Other

250 litres per hose pipe use

30 litres per bucket wash

6% (‘Other’)

N/A and ‘Maximum fittings consumption optional requirement level’ Table 2.2 of Approved Document G of the Building Regulations (2015 edition with 2016 amendments).

*Here ‘full’ is used in a colloquial sense, referring to the level to which a person would typically fill the bath to in order to bathe, which is only usually around half of its total holding capacity before it would overflow.

**See EU Energy Label information based on average eco-programme cycle. Most new washing machines and dishwashers will be compliant with these minimums.