Changes to the NPPF – SuDS – Paragraph 182
On December 12th 2024 the government updated the National Planning Policy Framework (NPPF). The new NPPF has brought with it significant amendments affecting flood risk including changes to the Sequential Test and Surface Water Drainage.
In this post we’ll explore the changes to Chapter 14, focusing on Surface Water Drainage (SuDS).
Chapter 14 - Meeting the challenge of climate change, flooding and coastal change
The previous iteration of the NPPF focused toward major applications mirroring the change of the guard as of 2015 when the Environment Agency handed responsibility back to the Local Planning Authorities with a focus to Surface Water Drainage / SuDS. This led to the creation of the Lead Local Flood Authorities as part of the Flood Water Management Act.
Old Version, December 2023
175. Major developments should incorporate sustainable drainage systems unless there is clear evidence that this would be inappropriate. The systems used should:
a) take account of advice from the lead local flood authority;
b) have appropriate proposed minimum operational standards;
c) have maintenance agreements in place to ensure an acceptable standard of operation for the lifetime of development; and
d) where possible, provide multifunctional benefits.
New Version, December 2024
182. Applications which could affect drainage on or around the site should incorporate sustainable drainage systems to control flow rates and reduce volumes of runoff, and which are proportionate to the nature and scale of the proposal. These should provide multifunctional benefits wherever possible, through facilitating improvements in water quality and biodiversity, as well as benefits for amenity. Sustainable drainage systems provided as part of proposals for major development should:
a) take account of advice from the Lead Local Flood Authority;
b) have appropriate proposed minimum operational standards; and
c) have maintenance arrangements in place to ensure an acceptable standard of operation for the lifetime of the development.
Although the NPPF was written to be more major project focused, Paragraph 173 (old version) set out that in item C that when determining planning applications:
C: it incorporates sustainable drainage systems, unless there is clear evidence that this would be inappropriate;
This paragraph has been retained in the latest NPPF but has changed paragraph number 173 to now 181. What does this all mean? In our experience and exposure to development, we are actively seeing Surface Water Drainage being requested on minor through to major applications. Local Plan Policies of the more recent local plans have encouraged SuDS. Although the principles of SuDS are mirrored by all Local Authorities, the nuances of each policy and the requirements of each local authority can change depending on the environmental conditions, size and scale of development, and matters specific to that location.
Local Planning Policy Promoting SuDS for Developments
Below are two examples showing how local planning policy has already begun to promote SuDS for different developments. It can be observed that sight of the nuances of each local authority is critical in supporting a planning application and reducing the number of conditions and risk of rejection imposed.
Croydon – Policy DM25
Sustainable drainage systems are required in all development and should;
- Ensure surface run-off is managed as close to the source as possible;
- Accord with the London Plan Sustainable Drainage Hierarchy;
- Achieve better than greenfield runoff rates;
- Be designed to be multifunctional and incorporate sustainable drainage into landscaping and public realm to provide opportunities to improve amenity and biodiversity;
- Achieve improvements in water quality through an sustainable drainage system management train; and
- Be designed with consideration of future maintenance.
Sustainable Drainage Systems and Reducing Flood Risk
Policy DM25.3, Croydon Local Plan 2018, p.155, Croydon Council (2018)
Arun District Council – Policy W DM3 – Sustainable Urban Drainage Systems
To increase the levels of water capture and storage and improve water quality, all development must identify opportunities to incorporate a range of Sustainable Urban Drainage Systems (SUDS), appropriate to the size of the development, at an early stage of the design process. Proposals for both major and minor development proposals must incorporate SUDS within the private areas of the development in order to provide source control features to the overall SUDS design. These features include:
- Green roofs
- Permeable driveways and parking
- Soakaways
- Water harvesting and storage features including water butts.
Proposals for major development must also integrate SUDS within public open spaces and roads, reflecting discussion with the appropriate bodies. SUDS must therefore be integrated into the overall design of a development and must:
- Contribute positively to the appearance of the area, integrating access to allow maintenance of existing watercourses and the system
- Effectively manage water (including its quality)
- Accommodate and enhance biodiversity by making connections to existing Green infrastructure assets and
- Provide amenity for local residents (ensuring a safe environment)
- Retain the existing drainage network of the site and wider area,
- Be maintained in perpetuity, supported through a Maintenance and Management Plan/Regime, including its financing, agreed with the Local Planning Authority.
In order to ensure that SUDS discharge water from the development at the same or lesser rate, as prior to construction, developers must:
- Follow the hierarchy of preference for different types of surface water drainage disposal systems as set out in Approved Document H of the Building Regulations and the SUDS manual produced by CIRIA.
- Undertake up to six months groundwater monitoring within the winter peiod.
- Undertake winter percolation testing in accordance with BRE365.
- The proposed drainage system must be designed to ensure that there is no flooding on a 1 in 30 year storm event.
- The design must also take account of the 1 in 100 year storm event plus 30% allowance for climate change, on stored comes, to ensure that there is no flooding of properties or the public highway or inundation of the foul sewerage system. Any excess flows must be contained within the site boundary, and within designated storage areas.
Sustainable Urban Drainage Systems
Policy W DM3, Arun Local Plan, p.228-229, Arun District Council (2018)
We have witnessed the local authority request winter monitoring even for householder minor development. This just shows the scale of implementation and variance between various local authorities.
In addition to Local Planning Authorities (LPAs) implementing policy as mentioned over arching these LPAs are the Lead Local Flood Authorities (LLFAs) who in turn provide their guidance which should be adopted and implemented.
Talk to flood risk experts
We believe at Aegaea that SuDS are a critical component of planning and the recent changes in the NPPF reflect this as do the more recent local plans in order to better mitigate surface water achieving all 4 pillars amenity, attenuation, biodiversity and water quality where possible.
At Aegaea a dedicated team of experts who work across England as well as Scotland and Wales. Our team can support from concept through to design on minor through to major applications.
Where does this leave Schedule 3…. It certainly sets out the foundations for schedule 3 to be implemented and raises the awareness of the importance of SuDS to developers, LPAs and other stakeholders.
For advice on how the recent NPPF changes affect your development or any flood risk expertise, get in touch with our dedicated team.
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Further reading about the NPPF changes and flood risk.
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