Water Efficiency Calculations

Do you need water efficiency calculations for Building Regs Part G or CSH?

Stroma Tech carries out the water efficiency calculations required for new dwellings to comply with Part G of the Building Regulations and Code for Sustainable Homes.

Why do you need Water Efficiency Calculations?

Building Regulations Part G

Under Part G of the Building Regulations, a maximum water usage figure of 125L per person per day must be achieved.  Non-compliance may adversely affect a dwelling’s Standard Assessment Procedure (SAP) calculation, and consequently its Energy Performance Certificate (EPC) rating.

Code for Sustainable Homes

The Code for Sustainable Homes imposes targets related to water usage through the WAT 1 category.

  • Levels 1 & 2: less than or equal to 120L per day
  • Levels 3 & 4: less than or equal to 105L per day
  • Levels 5 & 6: less than or equal to 80L per day

Calculations must be submitted at both the design and ‘as built’ stages; if your specification is not on target to meet the required limits, our experienced assessors can provide advice on how to resolve this, ensuring a smooth submission to Building Control.


Here you will find some of our case studies.
Stroma Tech. All Rights Reserved
Part of the Stroma Group
Titanic Belfast, The Signature Building
Phil Carr