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Sustainable Drainage Systems

Sustainable Drainage Systems (SuDS) aim to reduce surface water run-off from developments. They also provide amenity and biodiversity benefits and improve water quality by mimicking natural processes. Cornwall Council takes a proactive approach in encouraging the use of SuDS for the management of surface water.

Unlike traditional drainage systems which convey water away as quickly as possible; SuDS aim to manage surface water flows and volumes close to their source. SuDS are more sustainable than conventional drainage methods because they:

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  • Manage runoff volumes and flow rates, reducing the impact of urbanisation, reducing flood risk;
  • Improve water quality;
  • Provide amenity areas which can improve community wellbeing;
  • Improve and provide wildlife habitats.

Further information about SuDS can be found on the susdrain website

Under Schedule 3 of the Flood and Water Management Act (2010), Cornwall Council under its role of Lead Local Flood Authority (LLFA) was required to establish a SuDS Approval Body (SAB). Cornwall Council could then approve, adopt and maintain SuDS features serving new developments.

However, in December 2014, the Government announced that Schedule 3 would not be enacted. Instead SuDS would be dealt with by strengthening existing planning policy. This change, which took effect on 6th April 2015, requires the Local Planning Authority (LPA) to make the final decision whether the proposed SuDS provision is proportionate to the level of flood risk affecting the site and/or impacts elsewhere.

Cornwall Council is no longer required to establish a SAB, but the LLFA is the statutory consultee for major developments which have surface water implications. 

Cornwall Councils Sustainable Drainage Policy aims to clarify the Council’s position with respect to sustainable drainage, following the partial enactment of the Flood and Water Management Act (F&WMA) in April 2010.

The Cornwall Strategic Flood Risk Assessment (SFRA) provides a tool to assess the flood risk in Cornwall. The SFRA provides information for the allocation of land for development. It also holds information for planners and developers to enable the management of development, to limit flood risk to people and property wherever possible and manage the risk elsewhere.

A Critical Drainage Area (CDA) is an area that has critical drainage problems and which has been notified to the local planning authority as such by the Environment Agency. In a CDA we expect new development to actually reduce flood risks downstream, rather than having just neutral impact.

There are currently 29 CDAs identified in Cornwall, within a number of communities. Maps and details of these CDA can be accessed from the links below.

Communities with Critical Drainage Areas:

View the flood risk mapping

This document contains non-statutory technical standards for the design, maintenance and operation of sustainable drainage systems. Systems to drain surface water from housing, non-residential or mixed use developments for the lifetime of the developments.

The 'Drainage Guidance for Cornwall' is currently under review. Please email the Flood and Drainage team via for any drainage guidance.

This guidance provides specific advice on Cornwall Councils requirements for highway design and construction, including surface water drainage systems

A changed approach to surface water sewers

The new rules come into force on 1 April 2020 which allow certain SuDS to be adopted by Water Undertakers if they meet the legal definition of a sewer. The basis of this new approach is explained in the Water UK booklet on the topic.

If you would like to receive direct updates when amendments to the above documents or policies are made, or when new documents are made available, please email

Who will control my data?

The Data Controller for all the information you provide is Cornwall Council, New County Hall, Treyew Road, Truro TR1 3AY.  Data Protection Registration Number: Z1745294

There’s something I don’t understand

If you need help in registering for updates please contact the Flood Risk and Coastal Asset team on telephone number 0300 1234 222 or by emailing  

How we will use the information about you  

The information you submit to the Council will be used to provide you with updates and notification of amendments to the content held on the Sustainable Drainage Systems webpages including policy and guidance documents and web page content.

Who else will we share your information with?

We will only use this information to update you when any changes or amendments are made to the Sustainable Drainage Systems webpages. If your contact information is provided to the Council outside of this request this will be covered by an alternative privacy notice and retention period. 

How will we look after your data

Your data will be held within Cornwall Council’s secure network and premises and will not be processed outside of (the UK/the EEA).  Access to your information will only be made to authorised members of staff who are required to process it for the purposes outlined in this privacy notice.

How long will you keep this information for?

The email address you provide will continue to be held by the Council, and you will continue to receive updates, until such time as you unsubscribe. To unsubscribe from these updates please send a further email confirming you no longer wish to receive these updates. On receipt of your request to be unsubscribed your details will be deleted.

Please be aware that your details will only be deleted from the Sustainable Drainage Systems webpages email distribution list. If your contact details have been provided to this department, or any other department within the Council, as part of an alternative service then this will be covered by a different privacy notice which will confirm the retention period.

What are my data rights?

Your personal information belongs to you and you have the right to:

  • be informed of how we will process it
  • request a copy of what we hold about you and in commonly used electronic format if you wish (if you provided this to us electronically for automated processing, we will return it in the same way)
  • have it amended if it’s incorrect or incomplete
  • have it deleted (where we do not have a legal requirement to retain it)
  • withdraw your consent if you no longer wish us to process
  • restrict how we process it
  • object to us using it for marketing or research purposes
  • object to us using it in relation to a legal task or in the exercise of an official authority
  • request that a person reviews an automated decision where it has had an adverse effect on you

How do I exercise these rights?

If you would like to access any of the information we hold about you or have concerns regarding the way we have processed your information, please contact:

Simon Mansell

Data Protection Officer


Cornwall Council

County Hall



Tel: 01872 326424


I don’t agree with something

We would prefer any complaints to be made to us initially so that we have the opportunity to see if we can put things right.  However,  if you are unhappy with the way we have processed your information or how we have responded to your request to exercise any of your rights in relation to your data, you can raise your concerns direct with the Information Commissioner’s Office

Tel No. 0303 123 1113

Website: Information Commissioners Office

Why do you need my information?

You have asked us to provide you with Sustainable Drainage Systems webpage updates, this information will be provided via email and therefore we need your email address. Without your email we will not be able to provide you with the service.

By requesting to be added to the register of updates you confirm you have read and understood the above information