Guidance

Dewatering and depositing silts from sustainable drainage systems (SUDS) on land: RPS 55

Updated 16 December 2025

Applies to England

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This publication is available at https://www.gov.uk/government/publications/deposit-and-dewatering-of-non-hazardous-silts/dewatering-and-depositing-silts-from-sustainable-drainage-systems-suds-on-land-rps-55

This regulatory position statement (RPS) does not change your legal requirement to:

  • have an environmental permit for a waste operation or a groundwater activity where one is required
  • register an activity as exempt where you are required to do so

However, the Environment Agency will not normally take enforcement action against you if you do not comply with these legal requirements provided that:

  • your activity meets the description set out in this RPS

  • you comply with the conditions set out in this RPS

In addition your activity must not cause (or be likely to cause) pollution of the environment or harm to human health, and must not:

  • cause a risk to water, air, soil, plants or animals

  • cause a nuisance through noise or odours

  • adversely affect the countryside or places of special interest

Activity this RPS applies to

This RPS applies to those responsible for dewatering and depositing silt from sustainable urban drainage systems (SUDS) that are not inland waters on land. For example, local authorities with adopted SUDS systems, landlords or site owners and sewerage undertakers.

This RPS only applies to SUDS that collect surface water drainage from:

  • roof drains
  • residential property driveways
  • private residential car parks
  • roads serving a limited number of residential properties, such as cul-de-sacs, home zones (residential streets where people and vehicles share the whole of the street space) and general access roads
  • private non-residential car parks, for example at schools and offices, but excluding retail and industrial premises

Conditions you must comply with

You must:

  • do sight and smell checks to assess if hydrocarbons are present in the silt and whether further assessment is required
  • follow the waste classification technical guidance, if further assessment is required to make sure the silt is not hazardous
  • remove physical contaminants such as litter from the silt prior to deposit
  • manage silt assessed as hazardous waste through a suitably permitted facility
  • deposit the silt as close as possible to the SUDS where the silt was produced
  • deposit the silt outside the catchment area of the SUDS on land you are responsible for
  • take appropriate measures to prevent silt runoff from silt deposits during heavy rain or loss of storage capacity in the SUDS
  • keep records for 2 years from the date of the last use of the RPS to show that you have complied with this RPS and make these records available to the Environment Agency on request

You must not:

  • dewater and deposit the silt in a groundwater source protection zone 1
  • dewater and deposit more than 5 cubic metres of silt per hectare over any 12-month period
  • deposit silt onto land adjacent to the SUDS and then move the silt further away, unless any such further deposits are authorised under an environmental permit

Things to note

Some SUDS features may be classified as inland waters. Inland waters can for example include lakes or ponds, whether natural or artificial. If you remove silt from inland waters you may be able to do this under a D1: depositing waste from dredging inland waters waste exemption instead of this RPS.

This RPS relates to an activity that the Environment Agency considers is potentially suitable to be an exemption under the Environmental Permitting (England and Wales) Regulations 2016. A change in law would be required for this.

When you must check back

The Environment Agency intends to review this RPS by 30 November 2028.

The Environment Agency can withdraw or amend this regulatory position before the review date if they consider it necessary. This includes where the activity that this RPS relates to has not changed.

You will need to check back from time to time, including at and before the review date, to see if this RPS still applies.

This RPS remains in force until it is removed from GOV.UK or is otherwise identified as having been withdrawn.

You can subscribe to email updates about this RPS. These will tell you if the RPS has changed and when it has been withdrawn.

If you cannot comply with this RPS

If you operate under this RPS but can no longer comply with it, you must:

Contact the Environment Agency

If you have any questions about this RPS, email enquiries@environment-agency.gov.uk with RPS 55 in the subject.

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