If you have an upcoming development in the London area which requires a sustainable drainage strategy, completion of the London Sustainable Drainage Proforma may be required. In 2019, the Proforma was launched in 33 of London’s Lead Local Flood Authorities (LLFAs).

In this article, we will discuss what the Proforma is, where it applies, why you need it, and what needs to be included in it. Read more to find out!

What is the London Sustainable Drainage Proforma?

The London Sustainable Drainage Proforma is a document that must be submitted by developers and building owners as part of their Sustainable Drainage strategy (SuDS). It applies to 33 London Local Authorities and is required as part of their planning applications. It works to provide a clear and concise way to present the information to Planning Authorities, and shows them that the SuDS hierarchy has been followed, and to support the Flood Risk Assessment and SuDS/Drainage Strategy report that has been provided to accompany the planning application.

You can access your authority’s information, resources, and download the Proforma through the government’s website.

Why is the London Sustainable Drainage Proforma Needed?

The aim of the Proforma is to set a standard for developers to ensure they submit the exact information needed by the Local Authority in their initial planning applications in regard to Sustainable Drainage design. This also, therefore, contributes to achieving greater consistency throughout the London Councils when it comes to application requirements and LLFA information requests.

It’s a win-win for both developers and Local Authorities as it helps reduce the need for additional information to be submitted, saving time and money on both sides. This also reduces the risk of delays to an already lengthy planning assessment processes.

In basic terms, the London Sustainable Drainage Proforma should be used to streamline the key outputs from your SuDS strategy to allow your Lead Local Flood Authority (LLFA) to quickly assess compliance with planning policy.

Nimbus Engineering SuDS Reports

When Do I Need to Submit a London Sustainable Drainage Proforma?

Well, if your development requires a Sustainable Drainage strategy and its in one of the 33 London areas then you will need to submit the Proforma as part of your planning application.

If you’re not sure if your development requires a SuDS strategy you can check out our previous blog on the topic.

In simple terms, a SuDS strategy is required by National Planning Policy if your development meets the following conditions:

  • A development with more than 10 dwellings
  • Commercial Floorspace over 1000m2
  • Development is located within an area at risk of flooding, or within an area identified as having critical drainage problems

What Do I Need to Put in the London Sustainable Drainage Proforma?

The Proforma which you download from the government website (linked above) has a template that details exactly what you need to fill out each section with. The document is divided into four sections:

  • Site information including the project outline and development proposal
  • Your proposed discharge plan plus what the existing drainage is, what the ground condition and infiltration rate are.
  • The drainage strategy – proposed SuDS measures and how this will impact surface water runoff rates at your site.
  • Any supporting information i.e. SuDS designs, maintenance strategies, and other summarising information.


The London Sustainable Drainage Proforma shouldn’t affect your plans for your development as much as it actually will help you by reducing costs and delays of submitting a planning application that is missing crucial elements.

What’s important is that the Proforma is filled out to the detail it requires in order to illustrate how your development is meeting Planning Policy and drainage strategy guidelines.

If you’d like to talk to an expert about the London Sustainable Drainage Proforma and how it will impact your development just get in touch with us and we will be happy to help, as we complete these regularly and have worked with all 33 Lead Local Flooding Authorities within London.

Nimbus Engineering SuDS Reports

Choose Nimbus for your SuDS Design

As Civil Engineering and Environmental consultants, we can give you early-stage advice for sustainable drainage designs to integrate into your development, allowing you to work around any constraints or risks, in a natural and ecological way.

If you need a SuDS report, Flood Risk Assessment and SuDS report or Flood Risk Assessment and Drainage Strategy Report, don’t hesitate to get in touch with an expert here at Nimbus Engineering. Our close relationship with the Lead Local Flood Authorities (LLFA) means you can be sure that you get the right solution for your project, no matter what size and wherever it may be.

Sadia Luckett

Written by Sadia Luckett

Sadia Luckett is the Director at Nimbus Engineering, specialising in foul and surface water drainage & SuDS.