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Wat 03 Water leak detection and prevention

Number of credits available Minimum standards
2 No


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

Assessment Criteria

The following is required to demonstrate compliance for:

One credit

  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.
  2. The leak detection system is:
    1. Audible when activated
    2. Activated when the flow of water passing through the water meter/data logger is at a flow rate above a pre-set maximum for a pre-set period of time
    3. Able to identify different flow and therefore leakage rates, e.g. continuous, high and/or low level, over set time periods
    4. Programmable to suit the owner/occupiers’ water consumption criteria
    5. Where applicable, designed to avoid false alarms caused by normal operation of large water-consuming plant such as chillers.

One credit

  1. One of the following types of flow control device is fitted to each WC area/facility to ensure water is supplied only when needed (and therefore prevent minor water leaks):
    1. A time controller i.e. an automatic time switch device to switch off the water supply after a predetermined interval
    2. A programmed time controller i.e. an automatic time switch device to switch water on and/or off at predetermined times.
    3. A volume controller i.e. an automatic control device to turn off the water supply once the maximum preset volume is reached.
    4. 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.
    5. 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.

Compliance Notes





Mains supply shut-off See criteria 1 & 2 There is no requirement for the leak detection system to shut off the water supply when the alarm is triggered (constant water supply may still be required for certain systems/operations).


Leakage rates See criterion 2 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/occupier’s usage patterns.


System criteria See criterion 2 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 and/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 3 Where there is a water utilities meter at the site/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 systems See criterion 3 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.


Single WCs See criterion 3 The flow control criteria for this issue do 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).


Ancillary or multiple buildings/units The criteria apply to the water supply to all buildings falling within the scope of the assessment.


No water supply to the building/unit See criteria 1, 2 & 3 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, 2 & 3 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.


Shell only

Where the installation of facilities within tenanted units/areas will be the responsibility of the future tenant, compliance with the flow control credit within this BREEAM issue can be demonstrated via one of the following means for shell only buildings/areas:

  1. Option 1 – Use of a tenancy lease agreement between the developer and tenant/s (full value of available credits)
  2. Option 2 – A Green Building Guide for tenant fit outs (half the value of the available credits)
  3. Option 3 – Developer/Tenant collaboration (full value of available credits)

Refer to Appendix D – BREEAM New Construction and shell and core/speculative assessments of this Scheme Document for further description of the above options.


Multi-residential buildings and guest accommodation: flow control specification See criterion 3 The credit for the specification of flow control devices in WC areas/facilities does not apply to ensuite facilities in residential areas e.g. ensuite 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 with guest bedrooms with ensuite facilities, e.g. hotel rooms, and communal WC areas/facilities, e.g. communal WC facilities in hotels/hostels and care homes.


Clinical areas in healthcare buildings The criteria for this issue do not apply to toilet facilities in clinical areas.

Schedule of Evidence

Ref Design stage
Post-construction stage

Relevant section/clauses of the building specification or contract

Design drawings

Manufacturers product details

BREEAM Assessor’s site inspection report and photographic evidence

Manufacturers product details

Additional Information

Relevant definitions

Clinical areas
Hea 01 Visual comfort.

Checklists and Tables


Calculation procedures


Other information