This is a brief explanation of what is needed and how it is done. It can be a bit boring to read although I have tried to cut through the jargon as much as possible.
Procedure for Preparation of Drawings

Planning and Building Regulation applications are dealt with by your Local Authority and those departments each have a particular purpose -
Planning applications to show how the proposal fits into the environment and local character and the Building Regulation applications to show the building is constructed correctly.

These two departments do not always communicate with each other.

Depending on the purpose of the application sometimes just one approval is needed and not the other and other times both are required. Just to complicate the issue, sometimes approval is needed from your Water Authority especially if any proposed building is close to or over a Public Sewer.

In October 2008, changes were made to the planning system which were intended to make applications easier. However, in some respects it has become more difficult. To obtain further information on this “simplified” system please visit the Planning Portal website

If at all possible I suggest that you make a personal visit to your local council planning department to speak to the duty planning officer. That person will be able to advise what planning procedure is required. Although duty officers are available most times, it is advisable to phone to make sure. It is very helpful if you are able to take some printed photographs of the property especially of the area where you want to build as this will help the planning officer to give the best advice. ALWAYS make a note of the date and time and the officers name together with an outline of the advice given as this might be needed to complete application forms later.
When you are at the councils office ask if there is a Public Sewer on the site and where it is located.