SuDS Assessments



Sustainable Drainage Systems

Sustainable Drainage Systems, also known as SuDS, help to reduce the risk of surface water flooding. This is achieved by managing the surface water run-off as close to the source as possible and reducing peak flows entering sewers or watercourses.

Planning applicants, Architects, Planning Consultants and Property Developers will all want a firm understanding of SuDS systems, reports and designs before submitting a planning proposal. From April 2015, a SuDS Assessment became compulsory in certain situations and for all major developments.

small stream next to residential area. example of Sustainable Drainage systems


Helping your development achieve compliance

In the UK, the planning regulations for Sustainable Drainage Systems (SuDS) are outlined in the Flood and Water Management Act 2010 and the National Planning Policy Framework (NPPF) of 2012. These regulations were updated in 2015, with the introduction of the Statutory Instrument 2015 No. 596, The Town and Country Planning (SuDS) (England) Regulations 2015.

The 2015 regulations require all new developments in England of more than one dwelling or where the construction area is 100 square metres or more to include a sustainable drainage system as part of the planning application process. This system must be designed to manage surface water runoff from the development site in a way that reduces flood risk, improves water quality and enhances biodiversity.



How we work for you

SuDS Assessments can be written as separate reports or issued with our Flood Risk Assessments, and will improve the chances of achieving planning permission, as well as reducing the threat of flooding to the site and surrounding area, and potentially improve local amenities, and increasing biodiversity.

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benefits of sustainable drainage systems (suDS)

One of the primary benefits of SuDS is their capacity to reduce flood risk by efficiently managing surface water runoff, thus alleviating the strain on conventional drainage systems during heavy rainfall events. Additionally, SuDS promote environmental protection by facilitating natural filtration and pollutant removal, resulting in improved water quality as rainwater infiltrates the ground. This not only benefits local ecosystems but also contributes to the sustainability of urban development by reducing the impact of construction on existing drainage infrastructure and nearby water bodies. SuDS further enhances resilience to climate change, proving cost-effective over time due to lower maintenance requirements, and can enhance the aesthetics and amenity value of urban areas.

SuDS implementation in the early stages of your planning will increase the likelihood of your planning application being approved the first attempt.

Applicants and Property developers will benefit from the reduced risk of flooding on their development site, as well as a reduction in cost to construct, implement and maintain these systems and assets




Grey Concrete Tile With Cells Of Eco Parking drainage system

suDS assessments and reports

SuDS reports play a crucial role in the planning application process, demonstrating a developer's commitment to local flood prevention within or near the new development area. It's advisable to engage a SuDS specialist early in the planning phase to avoid potential delays and unforeseen issues later on. Once the SuDS report is submitted, the local authority will review various conditions, including SuDS components and materials, flood mitigation measures, foul water drainage, and surface water drainage. Construction can commence on-site once all necessary conditions have been satisfactorily met.

It's important to note that SuDS Assessments are mandatory in many situations across England. According to the 2015 regulations, all new developments in England consisting of more than one dwelling or with a construction area of 100 square meters or more must incorporate a sustainable drainage system as part of the planning application process.


SuDS reports typically include the following:

  • Surface water run-off calculations before and after the development
  • Exceedance route plans for the contributing area
  • Infiltration tests and assessment of the SuDS hierarchy
  • SuDS storage sizing and surface water attenuation calculations
  • A proposed drainage strategy and layout plans that are in line with national and local policy
  • Hydraulic calculations
  • Proof of feasibility for the SuDS Design plan
  • A maintenance and management plan for the lifetime of the property

Flume's team of flood risk consultants offer a professional and holistic approach to SuDS planning and reporting significantly enhances the likelihood of your planning application being accepted on its initial submission. We have cultivated our reputation by providing cost-effective services that prioritise sustainability in every project, aligning seamlessly with local government policies and delivering within timelines tailored to your requirements. Our extensive experience guarantees comprehensive coverage of all essential aspects in our reports.



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