05 Water

Alternative calculation method - KBCN0547

Where it is not possible to use the standard approach to determine the building’s total water consumption, the assessment can be completed on an elemental basis. This applies even in cases where the Wat 01 Excel calculator tool has a section for a broader building type, but the defined activity areas do not match the specific project under assessment. For example, although Wat 01 calculator includes a retail calculator, bars and restaurants should be assessed using the alternative calculation method, as no relevant data is available for the specific activity within retail. Where the activity areas of the building under assessment do not allow using the relevant building type’s calculator, then the alternative calculation approach should be used.

BREEAM New Construction UK 2018 – Post-Occupancy Stage assessment - KBCN1532

Following the publication of UK NC V6 it was announced that the Post-Occupancy Stage (POS) assessment within BREEAM will close with immediate effect. While we will no longer be offering this as an assessment option, the essence and intent behind the criteria will remain. At this stage, we will not be re-issuing the UKNC 2018 manual. Therefore, reference to POS will remain within the following issues:

Ene 01 Reduction of energy use and carbon emissions (two credits for Post-Occupancy Stage)
Ene 02 Energy monitoring
Wat 01 Water consumption
Wat 02 Water monitoring

To award the relevant credits, the references to ‘Post-Occupancy Stage assessment’ should be read as ‘Post-Occupancy Evaluation’ and carried out with the same intent; to understand and close the performance gap. For assessments that have been certified at Post-Construction, are in progress or are new assessments, the Post Occupancy Evaluation process should continue to be followed, however there is no formal post-occupancy BREEAM certification stage. Rating systems such as BREEAM in-Use and NABERS UK Energy for Offices are examples of tools that can be used to measure performance in the operational phase.

18-05-23: KBCN edited to illustrate that credits can be awarded.

Commercial dishwasher appropriate data - KBCN0687

If the component is present in the building but the appropriate data is unavailable from the manufacturer's product information i.e. uses a different unit of measurement, then the baseline performance level for the specified component should be used in the WAT 01 calculator. BRE Global is unable to provide a calculation method to convert data in to the correct unit for the WAT 01 calculator tool.

Domestic hot water supplied by a circulation loop - KBCN1017

Where a circulation loop is used on the domestic hot water supply, it is acceptable to only sub-meter the cold water supply. Sub-metering such systems may be impractical and the occupant can use the cold water meter readings as a proxy for overall water usage in relevant areas.

Erratum – up to v1.0 – issue overview icons - KBCN1070

Some icons in the recently published UKNC2018 technical manual indicate incorrect numbers of credits available by assessment type. The table below summarises the error and correction needed.

12-Oct-2022 - Title amended for clarity.
10-Aug-2018 - Technical manual updated. Only relevant to v1.0 of the manual.

Fire hydrants and sprinklers - KBCN0680

To meet BREEAM compliance, emergency systems such as fire hydrants and sprinklers need also to be covered by a leak detection system. The leak detection system must cover all mains water supply between and within the building and the ‘site boundary'.

Flow control devices – combining flow control - KBCN1034

Flow control devices are not required for each individual fitting and may control one or more WC area, such as adjacent male and female toilets within a core. However, when using a single device to control the supply to multiple areas, the strategy must account for the occupancy and function of each space, to ensure that the aim of the criterion is met. Combining multiple cores with varying occupancy using a single flow control device has the risk that faults in infrequently used sanitary facilities could continue to leak undetected.

Flow control devices – Use of devices on individual sanitary fittings - KBCN1550

The intent of the requirement for flow control devices is to minimise the impact of undetected wastage and leaks from sanitary fittings and supply pipework. The use of flow control devices on individual sanitary fittings alone does not, therefore, fully meet this aim.

Flow control devices for multiple blocks - KBCN1186

The criteria are set to encourage isolation of the water supply to each WC block when it is not being used. If a single flow control device, for example one programmed time controller, is adequate to switch the water on at predetermined times that suit the usage patterns of more than one WC blocks or facilities, this can be used to demonstrate compliance. Please note that if only one timed controller is used for a large area/number of facilities, the assessor must justify that this is appropriate to the usage patterns within the building and confirm that multiple timers would be redundant (i.e. they would all be set to the same time). Consideration should be given of any facilities that may be open longer than others, requiring these timers to be programmed differently in different areas. As long as the aim of the credit (‘to reduce the impact of water leaks that may otherwise go undetected’) can be achieved through the specification of an appropriate number of flow control devices, the credit may still be achieved if timers cover more than one WC area/facility to prevent minor water leaks.

14 Apr 2023 - Applicability to BIU V6 Commercial confirmed.

Flow control devices on rainwater supply for toilets - KBCN0868

Flow control devices will be required on water supplied from rainwater and serving the toilet facilities. Rainwater tanks are topped up by mains water and leaks could reduce levels of stored water and hence increase the use of mains water. The leak detection requirements apply to all relevant water systems, regardless of the water source.

Flow control devices – use of time controllers - KBCN1037

Where a time controller can be justified as an effective means of activating a flow control device, for example, where the facilities are in constant use for a fixed period each day, this may be considered compliant. BREEAM seeks to be outcome-driven and to encourage the most appropriate solutions in meeting the aim of the criteria.

Flow rate for a mixture of taps - KBCN0173

Whichever is the higher of the 'average flow rate' or the 'proportionate flow rate' should be used within the Wat 01 Calculator.

Flow restrictors - KBCN0976

If a flow restrictor can be demonstrated to effectively reduce the flow of water and it is integral to the fitting or supply pipework (ie not easily removed by the building occupant), this can be accounted for in calculations for this Issue. Such devices must be fit-for-purpose. Proprietary flow restrictors, therefore partly-closed isolation valves, for example, are not an acceptable solution.

Flushing control – patients with frail or infirm hands - KBCN0414

When determining whether the WC fittings in healthcare facilities are suitable 'for operation by patients with frail or infirm hands', the assessor should be satisfied that this requirement has been met, as it will be product type dependent. If unclear to the assessor, evidence obtained from the relevant manufacturer confirming that their product is specifically designed, and has been tested and approved, for this purpose would be acceptable.

16/04/2018 Rewritten for clarity

Leak detection – extent of responsibility - KBCN0688

For the credit to be awarded, all the pipework in a development that the owner/occupier has responsibility for must meet the leak detection criteria. In situations where third party organisations place restrictions on the pipework that can be metered, the scope of works (and hence placement of a meter for the use of leak detection) will start immediately after this point. For instance where the utility company's meter is placed midway between the boundary and the building, the scope of leak detection for BREEAM purposes will be between utility meter and the building, not to the boundary (as stated in the guidance). The scope of the BREEAM criteria is only on pipework that the owner/occupier has control over.

Leak detection – inseparable building and site boundary - KBCN0388

Where there is no distinction between the site boundary and the building; the utility meter being either located on the boundary or within the building, the leak detection criteria apply to the mains water supply within the building only. The BREEAM criteria apply to the pipework that the owner/occupier has responsibility for.

Leak detection – recycled water use - KBCN0433

The leak detection requirements still apply to all relevant water systems where water recycling systems are specified for WCs and urinals. Recycled water should be considered as a valuable resource as it replaces potable water use and, in many instances, recycling systems will still incorporate a mains-water back up.

Leak detection – using a BMS - KBCN0439

A BMS can be used for leak detection purposes if it can be demonstrated that its integrated or add-on features meet all the requirements for a leak detection system.

07 Feb 2022 - Applicability to BIU V6C confirmed

Leak detection between building and utilities meter - KBCN1116

For all pipework which is the responsibility of the building owner or occupier leak detection is required between the building and the utilities water meter. This requirement is applicable regardless of the length of the pipework. Where it can be demonstrated that it is not physically possible for a meter to be installed on the pipework, the requirement for leak detection between the building and the utilities meter can be considered not applicable, and the credit awarded based on the leak detection within the building.

Leak detection system notification - KBCN0245

So long as the compliant system alerts the appropriate person to the leak so they are able to respond immediately, the assessor can judge if the aim of the issue is being met by a reliable, robust and fail-safe means of notification.

Leak detection technologies – Compliance Principle - KBCN1566

Where it can be demonstrated that alternative water leak detection technologies can meet or exceed the capabilities of systems set out in the BREEAM guidance, subject to approval, these can also be considered compliant. It is the role of the Assessor and the project team to provide evidence and justification in a compliance principle query (see KBCN1555). The following alternative solutions are currently recognised:

Smart leak detection systems that are based on 'self-learning' (machine learning) to determine normal water use patterns are an acceptable alternative to systems that require manual pre-sets or manual programming.

Majority of water demand from rainwater harvesting - KBCN0860

If the majority of water use is supplied by sources other than mains or private water, for example rainwater harvesting, and this use will be monitored, additional metering of the smaller water demand that is masked by the larger demand is not necessary.

Manual watering - KBCN0553

Where the design team can justify that manual watering provides a reduction in unregulated water consumption, this can be considered as an acceptable method for reducing unregulated water use.

Measuring the flow rate of domestic components - KBCN0641

On site testing can be carried out by an appropriate professional to determine the flow rate and capacity of domestic components. This must be overseen by the client’s facilities manager and as-built drawings must be provided to confirm the presence and location of the components and any flow restrictors. Note that the conditions under which the testing is completed must be recorded, e.g. the pressure and the temperature of the water for taps. The assessor could conduct the test provided they are able to carry it out accurately.

15/02/2021: amended to cover all component types.

Metering recycled water - KBCN0658

Water-consuming plant or building areas consuming 10% or more of the building’s total water demand need to be sub-metered. This applies to recycled water, such as rainwater, grey water or process water as well as mains water. The aim of the Issue is to encourage reductions in water consumption, which is beneficial, regardless of its source. Monitoring the use of recycled water, may also help to reinforce the benefits of doing so and encourage further reductions.

Process water to offset potable water demand - KBCN0586

Where it is demonstrated that it is safe to do so, process water resulting from the building under assessment, can be considered for off-setting potable water demand from components that would otherwise be supplied using potable water, when in line with the criteria requirements for greywater systems. Process water resulting from the building under assessment can be considered as a form of greywater for the purposes of off-setting potable water demand.

21 Dec 2021 Additional wording added, requiring it to be demonstrated that process water is safe to use and KBCN applied to BIU standards.

Rainwater harvesting standard – BS 8515:2009 replacement - KBCN1179

BS 8515:2009 (+A1:2013 where relevant) has been withdrawn and replaced by BS EN 16941-1:2018, which can be used for new assessments. The basic approach in BS EN 16941 is equivalent to the intermediate approach in BS 8515 is. The detailed approach is still described in the same way.

The relevant schemes will be updated in the next reissues.
03.11.2021 Issue 2.0 of the UK RFO technical manual amended.

Sanitary fittings used in religious practices – updated - KBCN1624

Such fittings should not be included in the scope of this Issue. Please refer also to KBCN0418 This guidance relates to fittings and facilities used in some religious practices, for example, for washing before prayer.

03 Nov 2023 - Updated. Previous guidance was incorrect and contradicted the approach outlined in KBCN0418

Self-contained dwellings or units with individual utility meters - KBCN0199

Where self-contained dwellings or units covered by the assessment have their own individual energy supply and utility meter (e.g. water, gas or electricity), this supply can be excluded from the scope of the issue. All shared energy supplies and common areas under the responsibility of building management are still included in the assessment. For example, if self-contained flats in an assisted living development have individual gas supplies with their own utility meter, this supply will be excluded from the assessment. However, the lighting and small power comes from a shared distribution board on each floor, in which case this shared supply will need to be sub-metered in accordance with the criteria. This same principle applies to scenarios involving speculative industrial or retail units with capped services, where these units have their own utility meter.

12/09/2018 Applicable to Water Monitoring Issue where appropriate
27/09/2017 The word 'units' added to include a wider range of scenarios falling under this principle.
17/06/2022 Added other industrial / retail situations for further clarity on the applicability of this KBCN.

Shell only assessments – demonstrating compliance - KBCN0771

It is recognised that shell only developments may only include a capped-off water supply, with responsibility for installing the water meter and leak detection system resting with the incoming tenant. In such cases, compliance can be demonstrated where the spatial arrangements, distribution strategy and infrastructure can be shown to facilitate future compliance. This could be demonstrated by evidence such as schematic drawings showing how compliance can be achieved for the assessed development at the fit-out stage. Whilst shell only assessments are intended to consider only aspects which fall within the scope of such developments, in order that the aim of the Issue can ultimately be met, the works should not preclude future compliance.

Shower with multiple shower heads - KBCN0855

To calculate the water use of a shower with more than one shower head, one of the following should be done:

If all of the shower heads can be turned on at once, the flow rates should be added up.
If the shower heads can only be used one at a time, the highest flow rate should be used

22 Feb 2024 - Applied to BIU, BREEAM NC and RFO standards

Simple Buildings – connection to BMS - KBCN1405

For Simple Building assessments, criterion 3b does not apply. Simple Buildings generally do not have BMS, or other complex monitoring and management systems.

This is a manual error which will be corrected in the next re-issue.

Specialist assisted baths in care homes - KBCN0228

Specialist assisted baths in care homes or similar specialist applications can be excluded from the assessment of this issue. Due to the specific access and care needs of users, it may not be possible to reduce the volume of specialist assisted baths.

Sub-metering technologies – Compliance Principle - KBCN1561

Where it can be demonstrated that alternative sub-metering technologies can meet or exceed the capabilities of systems set out in the BREEAM guidance, subject to approval, these can also be considered compliant. It is the role of the Assessor and the project team to provide evidence and justification in a compliance principle query (see KBCN1555). The following metering standards or technologies are currently recognised as alternatives to pulsed output meters:

M-bus. I.e. systems that comply with the EN 13757 series of standards. Also includes systems complying with the OMS (Open Metering System) standards.

Temporary irrigation systems - KBCN0147

Temporary watering arrangements set up purely to allow plant species or a green roof to establish are acceptable for plants relying on natural precipitation during all seasons of the year. Where this is the case, the ecologist's report must confirm the plant species and the expected time for recommended plant species to establish themselves i.e. time period for temporary watering arrangements.

Urinals – calculation of litres/bowl/hour - KBCN1010

A flushing frequency of two flushes per hour is used in the Wat 01 tool and should be applied when calculating the volume of water dispensed by urinals and compared against the water efficient consumption levels by component type for the Wat 01 issue. This method should be applied to calculate litres/bowl/hour. For example, a 13.5 L cistern feeding 3 bowls which is flushed 2 times per hour: (13.5 L / 3 bowls) x 2 times an hour = 9 litres/bowl/h.

Using water from natural underground sources to offset water consumption - KBCN00094

Water from natural underground sources (for instance aquifer water accessed via boreholes) cannot be used to offset:

NC / RFO: potable water consumption.
IU: utility supplied water consumption.

A significant amount of water used for public consumption is already drawn from aquifers. Private boreholes may be drawing water from the same sources as public utility companies.

27-Mar-2024 - Title and text updated to broaden definition. Scheme applicability updated.

Washer dryers - KBCN0699

Where a washer dryer is specified, the water consumption figure for the wash and dry cycle should be used. The drying cycle of a washer dryer is taken into account because it usually uses water during this drying process (e.g. for cooling during the drying cycle) and in some cases, this water usage can be significant.

18-Nov-2022 - Updated to apply to BREEAM In-Use Version 6

Washing machines and dishwashers – Water consumption data - KBCN1571

The water consumption data used to demonstrate compliance may be based on the lowest full wash cycle (i.e. not a pre-wash cycle, for example).

Water consumption calculation for sensor taps - KBCN0180

The water flow rate of sensor taps can be entered directly into the flow rate cells of the Wat 01 tool. The amount of water dispensed by sensor taps for each use is determined by occupant demand in the same way as normal taps. Therefore, the default frequency of use will be applied in the Wat 01 tool and no adjustment calculation is needed for sensor taps.

Water fittings specification evidence at design stage - KBCN0420

For a design stage assessment, it is acceptable to provide data based on reasonable assumptions if the final specification of fittings is not yet available.

Water fittings used for a process related function - KBCN0418

Water fittings used for a process related function, e.g. low level ablution taps, laboratory / classroom taps, scrub-up taps, cleaners' sinks etc., should be excluded from the assessment of regulated water consumption. Only kitchen taps and those used for general hygiene washing are to be included in the assessment of regulated water consumption.

04/08/17 Added low level ablution taps (typically used for religious purposes) to exemptions.

Water monitoring when only part of a building is under assessment - KBCN0548

When only part of the building is under assessment, there are two cases for achieving compliance with the requirement to specify a water meter on the mains water supply of the building: If the whole building is under the same tenancy or ownership and management, then a meter monitoring the entire building is acceptable. However, if the floors subject to assessment are separately tenanted, then a meter at the point of entry to the assessed areas is required. Assessed areas have to be monitored separately for water consumption when only part of the building falls within the scope of assessment and where the assessed areas are separately tenanted.

New Construction / UK / 2018 /