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Reina Compliance – Water Consumption services

Whole House Potable Water Consumption Calculation

Assessment Procedure

Appendix A of Building Regulations Approved Document G sets out a calculation methodology for assessing the whole house potable water consumption in new dwellings.

This methodology was also previously used to assess water consumption under the Code for Sustainable Homes ‘WAT2’ category

Technical Competence

Whilst there is no accreditation scheme currently associated with the above calculation method our assessors have previously been accredited with Stroma Certification under the now withdrawn Code for Sustainable Homes scheme.

Building Regulations

To comply with current Building Regulations Approved Document G2, potable water consumption must be no less than 125 lpppd in addition to this, depending on certain planning conditions there is an optional requirement to achieve a lower water consumption rate of 110 litres per person per day.

Calculation Procedure

The calculation includes all the water consumption used in the house, including sink and basin taps, toilets, baths, Washing Machine, Dishwasher, Water Softener and Waste Disposal Unit and makes an allowance for external water use. Consumption may be offset by water saving or recycling devices.

Assessment Preparation

To accurately produce the “WAT 2 ” calculation it will be necessary to obtain the following information:

Flow rate (@3bar) of all varieties of sink and basin taps, flush capacity of toilets (which may be single or dual) capacity of each bath, flow rate (@3bar) of all varieties of shower head, specifications for washing machine, dishwasher, water softener or waste disposal unit that will be installed by the developer Details of any rainwater or grey water recycling devices installed or provision for them.

To learn about what mechanical plumbing and heating services we provide please see Reina Contract Plumbing.

For more information regarding all our Reina Compliance services and Reina Water Consumption Services please contact us on 01303 248648 or email

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