Surface Water Drainage Assessment (SWDA) Guidance and Validation Tool

The level of detail varies depending on the development type, size and location. To help simplify the process we have developed a web-based validation and advice tool. The webtool can be used:

  • to identify what level of detail is required to meet the validation criteria,
  • provide advice on meeting the requirements and
  • to generate a Drainage Assessment for small developments as a single document ready to be submitted with your planning application; or,
  • to generate a site specific list that can be sent to the drainage engineer.

Who should use the SWDA and validation tool?

This replaces the validation checklist so is suitable for everyone and should be used by everyone that wishes to submit a planning application. Using this tool will help ensure it can be validated quickly and that the consultees have all the information to be able to assess the application.

Open the drainage assessment tool

  1. Site Details

    The first part of the process is to provide site and development details to generate a bespoke Validation checklist.

  2. Identify Drainage Options

    Sustainable drainage solutions need to follow the drainage hierarchy and use infiltration as the first choice. This step will help identify the options available and if any testing or permissions are needed.

  3. Drainage Assessment Summary

    The summary will identify the risk and highlight what further details are required.

  4. Prepare the required documents

    Supporting information is essential to complete the Drainage Assessment and make sure your application can be processed as quickly as possible.

  5. Create your drainage assessment

    The SWDA must include all the required testing, calculations and plans in a single PDF document.

  6. Submit your application

    If you decide to make a planning application then you will need to submit the drainage information on this page.