Part G Water Calculations

Mandatory assessments to determine the water usage levels of your new build or conversion

Measuring water usage and supporting sustainability targets

Many water calculations rely on default values, leading to discrepancies between certificates and actual fittings. This can result in overestimated consumption and failing compliance, both of which will hinder a project’s progress.

Our energy consultants will complete calculations based on the fittings installed to ensure accuracy and compliance. By eliminating default values, we provide a reliable calculation process and a Part G water certificate that accurately reflects your property’s sustainability merit from a water usage perspective.

Why do you need this service?

Regulatory
compliance

A Part G water calculation will ensure your build adheres to Building Regulations and a full Part G compliance certificate can be issued.

Water 
efficiency

Water calculations will help to reduce overall water consumption at your property, keeping operational costs low for its occupants.

Sustainability
first

Taking steps to reduce water consumption promotes better resource management and a more environmentally conscious design.

Our Process

Collect the data we need,

gathering information such as fixtures installed on the floor plans.

Calculate the usage,

assessing water consumption based on project-specific details.

Report on the results,

providing clear, easy-to-follow documentation.

Suggest ways to improve the calculations,

perhaps by optimising flow rates and adjusting non-compliant fittings.

Conduct cross-checks

to verify that as-built fittings match design specifications.

Issue certification,

delivering your final Part G compliance certificate.

Why choose Energy Digest?

Avoid inaccurate default values and benefit from a diligent and thorough water usage calculation service that ensures the best results for your project and your building’s occupants. 
We regularly support our clients by providing water efficiency calculations for new builds, major renovations, and compliance checks that take place before final project approval.

Our priority is always to deliver precise calculations, which is why, in the later stages of your project, we will cross-reference the fittings that have been installed to ensure our reports reflect the actual water performance of your building. We can even advise on the fittings that will deliver maximum efficiency.

Fast turnaround time

To help you meet your own deadlines, we’ll ensure your water calculations are issued within 24 hours.

Multi-disciplined team

We cover 20+ services in the built environment, with specialists providing high-value calculations and strong advice.

Practical solutions

Our professionals provide recommendations that are calculated to ensure real world outcomes, resulting in cost-effectiveness and high impact.

Unrivalled support

Our service doesn’t end with the reports. We can provide ongoing support and expertise, from planning to completion.

Speak to our
experts today

FREQUENTLY ASKED QUESTIONS

Water Calculations
FAQs

An assessment under UK Building Regulations to evaluate water efficiency in new builds and renovations, ensuring usage stays within set limits.

The standard limit is 125 litres per person per day, with 110 litres or lower required for specific projects or local mandates.

Flow rates of fixtures, water volumes for appliances and fixtures, and any greywater or rainwater harvesting systems are included.

While technically allowed, default values are not recommended, as they often overestimate water usage. Accurate calculations based on actual fixtures ensure compliance and avoid regulatory issues.

For all new dwellings, major renovations, and residential conversions to confirm compliance before project sign-off.

Compliance influences the selection of water-efficient fixtures and encourages sustainable solutions like greywater systems, reducing environmental impact and operational costs.

What are the components of
a water calculation?

We’ll typically measure three aspects to reach an accurate figure. First, we’ll look at your flow rates, which measures water flow from your taps, showers, and other fixtures. Then, we’ll assess the water consumption of toilets, baths, and appliances – aka your volume usage. Finally, we will evaluate the impact of any sustainable systems onsite, including greywater and rainwater harvesting solutions, if applicable.

Spoke with Josh who not only reassured me but asked for a fee that I thought was fair. Thank you Josh. Use again? Definitely.

Steve Quirk

The team really know their stuff – super helpful and always had clear answers to any questions or compliance issues we ran into. Definitely our go-to for any future projects!

Nathan Donnelly

Quick and well priced water calculation service and received an appliance specification report alongside the certificate which was really useful for us and the building control officer, highly recommended!

Ilma Akhtar

Very knowledgeable about building regulations, and the industry. Always goes the extra mile to help out! 5*

Karim Meraga

Still unsure?

We offer free phone call and email support until you’re ready to proceed with us.
Access free support for your project now.

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