This technical guidance sets out the requirements for the Code, and the process by which a Code assessment is reached. It aims to make gaining a Code assessment as simple, transparent and rigorous as possible.
The latest version is the 'May 2009 Version 2' guide which comes into effect on 22 June 2009. For homes registered on or after this date, the May 2009 Version 2 will apply. The October 2008 version (which is available in the related publications section) will only apply to homes registered before this date.
This technical guidance manual underpins the publication: The Code for Sustainable Homes: Setting the standard in sustainability for new homes  that was published on 27 February 2008.

A summary of changes between the October 2008 version of the Code for Sustainable Homes Technical Guidance and the May 2009 version can be found in the publication  Code for Sustainable Homes Summay of Changes Technical Guide - May 2009 Version 2 .
The indoor water use (Wat 1) section now uses the Water Efficiency Calculator (external link) for New Dwellings as the assessment.