Guidance on development and flood risk

Here developers and local planning authorities can find guidance to assist in creating suitable drainage systems.

Statutory consultation

The Flood and Water Management team at Suffolk County Council, is a statutory consultee for surface water drainage proposals for major developments  This is part of our responsibility as the Lead Local Flood Authority (LLFA) under the Town and Country Planning Order 2015

The revised National Planning Policy Framework, December 2023 (NPPF), Section 175, requires that all major development incorporates Sustainable Drainage Systems unless there is clear evidence that this would be inappropriate.

The definition of major development is:

  • the number of dwellings to be provided is 10 or more, or the development is to be carried out on a site having an area of 0.5 hectares or more (and it is not known if 10 or more dwellings are to be provided)
  • the provision of a building or buildings where the floor space to be created by the development is 1,000 square metres or more.
  • Development carried out on a site having an area of 1 hectare or more.
  • any minor applications in areas at risk of surface water flooding. You can determine whether a site may be at risk of surface water flooding using these maps created by the Environment Agency

We would encourage developers to contact us as early as possible in the planning process for advice on how to create an application which meets minimum operational standards and is beneficial for all concerned organisations and individuals.

Pre-application advice

SuDS Planning advice should be sought from the County Council as early on in the process as possible. Suffolk County Council offer a pre-app advice service in Babergh and Mid Suffolk District Councils, and West Suffolk Council. This is a charged service which covers a range of local government requirements in the planning process. Advice on flooding and drainage issues is available as part of this service. For more information, including pricing and how to apply, please see the pre-application page on Babergh and Mid Suffolk's website or the West Suffolk Council website.

Currently the pre-application service is confined to Babergh, Mid Suffolk and West Suffolk, but in the future we would seek to include more areas of Suffolk.

Suffolk Flood Risk Management Partnership

The Suffolk Flood Risk Management Partnership has created a number of useful documents which clarify what is required of developers and why. The first of these is the Suffolk Flood Risk Management Strategy which can provide developers some context into flood management for Suffolk on a larger scale, including key links to and extracts from key national guidance documents. The strategy document has a number of appendices which are the following:  

  • Appendix A - The Suffolk SuDS guide provides a steer as to what is expected by Suffolk County Council (LLFA)* and is derived from the CIRIA SuDS manual to complement national requirements and guidance, whilst reflecting the local environment.
  • Appendix B - A consenting policy which aims to provide clarification of the policy towards works affecting a watercourse, particularly culverts. Further information can be found on our working on a watercourse page 
  • Appendix C - A protocol for advising our local planning authorities (LPAs) exactly what is required from developers in terms of surface water drainage 
  • Appendix D - Guidance on how we deal with flooding reports 

*NB: this latest updated version has been made available for informative purposes at this stage. We encourage developers to start implementing the guidance contained within this document ASAP. However, SCC LLFA acknowledge the need for a transition period from old to new guidance. SCC LLFA intend to hold a developers event in summer 2023, which will give developers and consultants an opportunity to raise any queries they have with the new guidance and for us to address those queries. Subsequently, all new applications will be expected to fully comply with this guidance.

Local validation lists

Under the National Planning Policy Framework (NPPF) and local validation lists set by each local planning authority (LPA), developers will be required to fill out a number of different documents before their application can be registered. For flooding and drainage related matters these include:

  • A Flood Risk Assessment (FRA) when defined as necessary by the protocol, to demonstrate the flood risk to, and resulting from, the development and to demonstrate the safety of the development for its lifetime
  • Our surface water drainage proforma in order to speed up the planning process as much as possible
  • An asset collection sheet which allows us to capture new flooding and drainage assets as they are built. Another of our responsibilities as the LLFA is to create and maintain a Flood Risk Asset Register, and this information will assist that

Some applications may also require land drainage consents. Please see our information which outlines how you can obtain permission to work on a watercourse.

Other helpful resources

We have developed a piece of standing advice for Solar Panels (PV) and Solar Farms and how we expect to see flood risk and surface water drainage being managed.

Our Surface Water Management Plans (SWMPs) are available online via the Green Suffolk website.

Anglian Water's policy for SuDS and details of their pre-planning services are available online.

Suffolk County Council and Anglian Water have worked together to form the Suffolk SuDS Palette which helps developers and architects design SuDS systems which are in-keeping with the wider Suffolk landscape.

We have produced a Construction Surface Water Management Plan template for developers to use during the planning process. This document will guide developers, ensuring that you can submit the correct information first time therefore reducing unnecessary delays. You can find it on our Construction Surface Water Management Plan web page.

To find out whether there are existing flooding issues in the area you want to develop, you can request a flood map from the Flood and Water Management Team.

There is also comprehensive national SuDS guidance available, published by CIRIA, which details technical specifications for all sustainable drainage systems. To compliment this guidance CIRIA has also produced a number of helpful videos via susdrain, which outline the basics in delivering SuDS.

Suffolk's Preliminary Flood Risk Assessment (PRFA) is available to view online.

Suffolk Resilience Forum has plenty of information to assist LPAs and developers in ensuring their proposals meet the requirements for building on a flood plain.

A video of a presentation given to LPAs regarding the use of SuDS is available to view publicly.

Please contact the Flood and Water Management team at for any further questions.