Wat 03 Water leak detection and prevention

(all buildings)

Number of credits available Minimum standards
Building type dependent No


To reduce the impact of water leaks that may otherwise go undetected.

Assessment criteria

The following is required to demonstrate compliance:

One credit - Leak detection system

1 A leak detection system which is capable of detecting a major water leak on the mains water supply within the building and between the building and the utilities' water meter is installed. The leak detection system must be:
1.a A permanent automated water leak detection system that alerts the building occupants to the leak OR an inbuilt automated diagnostic procedure for detecting leaks
1.b Activated when the flow of water passing through the water meter or data logger is at a flow rate above a preset maximum for a preset period of time
1.c Able to identify different flow and therefore leakage rates, e.g. continuous, high or low level, over set time periods
1.d Programmable to suit the owner's or occupiers' water consumption criteria
1.e Where applicable, designed to avoid false alarms caused by normal operation of large water-consuming plant such as chillers.

One credit - Flow control devices (all buildings except residential))

2 Flow control devices that regulate the supply of water to each WC area or facility according to demand are installed (and therefore minimise water leaks and wastage from sanitary fittings).

One credit - Leak isolation (residential only)

3 Isolation valves are located in an accessible place that allows hot and cold water to be isolated by hand separately (switched on or off) for the following supplies:
3.a Incoming supply to the dwelling
3.b Taps
3.c Showers
3.d Heating or hot water systems
3.e Appliances (e.g. dishwasher, washing machine etc.).

Checklists and tables


Compliance notes




Shell and core (non-residential and residential institutions only)


Applicable assessment criteria

Leak detection system, criterion 1

Both options: All criteria relevant to the building type and function apply.

Flow control devices, criterion 2

Shell only: This criterion is not applicable.

Shell and core: All criteria relevant to the building type and function apply.

Leak isolation, criterion 3

Both options: This criterion is not applicable.

Refer to Appendix D – Shell and core project assessments for a more detailed description of the shell and core assessment options.


WC Areas or facilities

Shell and core:

The water supplies to WC areas or facilities must be assessed as per criterion 2 regardless of whether or not the WC areas or facilities are fitted out.

Residential - Partially fitted and fully fitted


Applicable assessment criteria - Single dwellings

Both options: Criterion 3 only applies.

Refer to Appendix E – Applicability of BREEAM New Construction to single and multiple dwellings, partially and fully fitted for a more detailed description of residential assessment options.


Applicable assessment criteria - Multiple dwellings

Partially fitted: Criterion 3 only applies.

Fully fitted: Criteria 1 and 3 apply.

Refer to Appendix E – Applicability of BREEAM New Construction to single and multiple dwellings, partially and fully fitted for a more detailed description of residential assessment options.



Leakage rates.

See criterion 1.

This issue does not specify what the high and low level leakage rates should be; however, the leak detection equipment installed must have the flexibility to distinguish between different flow rates to enable it to be programmed to suit the building type and owner's or occupiers' usage patterns.


System criteria.

See criterion 1.

It is anticipated that the leak detection credit will usually be achieved by installing a system which detects higher than normal flow rates at meters or sub-meters. It does not necessarily require a system that directly detects water leakage along part or the whole length of the water supply system.


Water utilities' meters.

See criterion 1.

Where there is a water utilities' meter at the site or building boundary, it may be necessary to install a separate flow meter (or alternative measurement system) just after the utility meter to detect leaks; however, if the water utility company agrees to some form of leak detection being installed on their meter, this would also be acceptable.


Flow control devices.

See criterion 2.

The following could be considered as types of flow control devices:

  • A time controller, i.e. an automatic time switch device to switch off the water supply after a predetermined interval
  • A programmed time controller, i.e. an automatic time switch device to switch water on or off at predetermined times
  • A volume controller, i.e. an automatic control device to turn off the water supply once the maximum preset volume is reached
  • A presence detector and controller, i.e. an automatic device detecting occupancy or movement in an area to switch water on and turn it off when the presence is removed
  • A central control unit, i.e. a dedicated computer-based control unit for an overall managed water control system, utilising some or all of the types of control elements listed above.


Flow control systems

Flow control systems may control combined WC areas, such as male and female toilets within a core; they are not required for each individual sanitary appliance. The criteria are set to encourage the isolation of the water supply to each WC block when it is not being used.


Accessible location.

See criterion 3.

Isolation valves must be located in an accessible location. This could be within a cupboard or access hatch, where the valve can be accessed without undue hazard or difficulty. The valve should be in close proximity to the appliance or fitting and clearly labelled. Examples of non-accessible locations are behind kitchen units or under floor boards.


Single WCs.

See criterion 2.

The flow control criteria for this issue apply to facilities which have only a single WC (potentially within smaller or low occupancy buildings). In these instances shut-off could be provided via the same switch that controls the lighting (whether proximity detection or a manual switch).


No water supply to the building or unit.

See criteria 1 and 2.

These credits are still assessed where there are no installed fittings and therefore no water supply to the building. In these instances the facilities likely to be used by the future occupants of the assessed building must meet the criteria, e.g. those facilities within the nearest accessible building.


Extensions to existing buildings.

See criteria 1 and 2.

If the water supply to the new extension is via the existing building then the water supply to the existing building must be assessed against the criteria of this issue.
Building type specific


Residential institutions and guest accommodation: Flow control specification.

See criterion 2.

The credit for the specification of flow control devices in WC areas or facilities does not apply to ensuite facilities in residential areas, e.g. ensuite facilities in individual private bedrooms and a single bathroom for a collection of individual private bedrooms in halls of residence, key worker accommodation or sheltered accommodation. The credit and criteria are however applicable to buildings which have guest bedrooms with ensuite facilities, e.g. hotel rooms, and communal WC areas or facilities, e.g. communal WC facilities in hotels or hostels and care homes.




Criteria Interim design stage Final post-construction stage

The relevant sections or clauses of the building specification or contract.

Design drawings.

Manufacturer's product details.

BREEAM Assessor’s site inspection report and photographic evidence.

Manufacturer's product details.

Additional information

Relevant definitions

Isolation valve
An isolation valve is a valve in a plumbing system that stops the flow of water to a given location for maintenance purposes. This enables the flow of water to a terminal fitting, appliance or whole system (e.g. a tap, washing machine, heating system or whole home) to be isolated, thus allowing maintenance or replacement of components or systems.

Other information