Part G Water Calculations

Greater Manchester EPC can provide quick, easy and bespoke reporting to get you through – whether you need Part G water calculations or the equivalent Code for Sustainable Homes reporting.

Why Part G Water Calculations?

Do you need to provide water calculations for building regulations or the Code for Sustainable Homes?

Building regulations demand that new builds meet the minimum 125L litre per-person-per-day limit. If the development is subject to the Code for Sustainable Homes, you will also be required to reduce internal potable water use further through the Wat 1 category. Each Code level sets a mandatory limit on internal water consumption – this is demonstrated by producing calculations, based on occupancy, fittings and flow rates within the water efficiency calculator.

Need help with Part G Water Calculations?

The current limits are set as follows:

  • Level 1 & 2 – Less than or equal 120L p/day
  • Levels 3 & 4 – Less than or equal 105L p/day
  • Levels 5 & 6 – Less than or equal 80L p/day

There are also credits available for meeting these targets.

A number of measures can be taken to reduce indoor water use. Flow restrictors are a convenient means to retrofit existing fittings. Low flow shower heads, low flush wc’s or even smaller baths may be fitted. Efficient appliances, grey water and rainwater recycling can also be specified. We can suggest solutions and products which are efficient, practical and cost effective.

The Water Efficiency Calculator for New Dwellings

Our bespoke Part G water calculations are based on “The Water Efficiency Calculator for New Dwellings” – The Governments national calculation methodology. This provides clear, concise information for both you and Building Control – meaning that you get signed off quickly and easily. We will receive:

  • Notice of Water Efficiency (as required by 37(1)
  • Summary page together with all corresponding completed tables
  • Separate “Design” (including Builders check list) and “As Built” Reports
  • Code For Sustainable Homes rating against Wat 1

Would you like to discuss your project?

Call us for a chat on 07875 753571 or email

If you prefer, use our quick and simple contact us form.

Tell us about your project?

We understand the building compliance process can be confusing. To discuss and advise on your project requirements call us on 07875 753571.


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Why not discuss your project with a member of our team? Call us today on 07875 753 571