Water Efficiency Calculations

Our highly experienced in-house team can quickly provide all of your Water Consumption Calculations and associated advice in order to help you demonstrate compliance with Part G of the Building Regulations or any other local planning requirement.

Our fees are extremely competitive with substantial discounts offered for developments with multiple units.

Water Consumption Calculations

At EPS Group we pride ourselves on forming constructive working partnerships with our clients. We provide unrivalled customer support and technical consultation focused on providing cost-effective and practical solutions to achieving compliance with Part G of the Building Regulations

We can provide water efficiency calculations within 24 hours by request and our expert advice and consultation will guarantee compliance with Part G or any additional planning requirement.

For more information relating toWater Efficiency Calculations, please explore the Frequently Asked Questions below.

Alternatively, to discuss your specific project in greater detail, or to obtain a FREE quotation please give us a call on 0115 7270599, email us at info@epsgroup.co.uk, or complete our enquiry form.

Why are Water Consumptions Calculations required?

Approved Document Part G of the Building Regulations requires all new dwellings (including conversions) to use less than 125 litres of water per person per day. This can be demonstrated by supplying Building Control with an appropriate water efficiency calculation at the design stage and on completion of a build.

Asides from the national mandatory requirements of Part G of the Building Regulations, there are also provisions for local planning authorities to set a more stringent water consumption rate of 105 litres per person per day, as part of their localised sustainability requirements. This often takes the form of a planning condition for the development.

Water Efficiency Calculations FAQs

How are Water Efficiency Calculations completed?

The projected water usage of a property is calculated in accordance with the Government’s published methodology “The Water Efficiency Calculator for New Dwellings”. The calculation considers the following:

  • The capacity of any installed baths
  • The flush capacity of all installed toilet cisterns
  • The flow rate of installed taps and showers including any restrictors that may have been installed
  • The specific water consumption of any installed washing machine
  • The specific water consumption of any installed dishwasher
  • The efficiency of any installed water softeners
  • The effect of any installed rain water or greywater harvestings systems

When should I complete a Water Consumption Calculation?

Ideally water usage calculations should be first completed at the design stage so that the specifications or design parameters of any fittings can be checked and where appropriate revised in order to ensure compliance targets are met. Once construction is finished, the design calculation is then updated with specific details of what has been installed prior to submitting the finalised water consumption calculation to Building Control.

Despite the above, it is commonplace for clients to only request a water efficiency calculation once they have finished building and the water fittings have been installed. Whilst this reduces the choices available for achieving compliance, we can still advise on any necessary remedial options if the initial water efficiency calculation fails.

What happens if I fail the Water Efficiency Calculation?

If the calculated water usage for a property is too high at the design stage, we can advise on number of potential revisions to the water fittings specification such as changing the number or fill capacities of any proposed baths or selecting showers or taps with a reduced flow rate. Alternatively, we can provide you with a set of design parameters to help you source compliant water fittings at a late date.

If the water efficiency calculation fails when property is built and all sanitary ware and water outlets are in place, compliance will still be achievable through the careful selection and installation of flow restrictors to taps and showers.

How can EPS Group help with Water Efficiency Calculations?

There are many reasons to appoint EPS Group to provide your Water Efficiency Calculations

How can EPS Group help with Water Efficiency Calculations?

At EPS Group we provide unrivalled customer support and technical advice focused on providing cost-effective and practical solutions to ensure that your water efficiency calculations meet the required consumption target.

We can provide your water consumption calculations as a low-priced standalone service, or as part of an overall building regulation compliance package incorporating SAP Calculations, On Construction Energy Performance Certificates and / or Air Leakage Testing.

Our water efficiency calculation service includes:


Fixed, low cost fees


Multidiscipline team providing a host of related services under one roof


Significant discounts for development sites with multiple units


Expedited service available on request


Independent client focused advice

EPS Group: A Partner for those in the Construction Industry

We value the importance of a solid working relationship with those in the construction industry, and for many, we serve as the reliable go-to-company to entrust from the planning stage of a development through to completion.

What Our Clients say:

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Water Efficiency Calculations project!

Jual Ahmed
Jual Ahmed
Excellent service from start to finish. I would highly recommend and will definitely use again. Thank you!
A great service and attended within a week of request. Polite knowledgeable engineer who completed the test quickly and efficiently...Thank you EPS
Steve Naylor
Steve Naylor
EPS group undertook the initial SAP design assessment, then the as-built assessment for my new property, including air test. They were super-responsive and made the appointment for the air-test within a few days of the request. The certificates were issued very promptly and they helped me through the process (I had never done this before). Really recommend them.
Nick Collingridge
Nick Collingridge
Great service from EPS Group. Their operative was friendly, efficient and very helpful. He carried out his survey quickly and then spent time walking round the property with me pointing out all the points at which air was infiltrating. He also passed on some invaluable tips about the best way to attend to the detailing of aspects of a property's structure to maximise air tightness. I am altogether very satisfied with the survey.
Mark Blood
Mark Blood
Have worked with EPS for several years now in connection with all of our energy assessment requirements. Extremely efficient service at very competitive fees and always available to offer advice on achieving compliance. Would definitely recommend.