Guidance

Using wetlands to improve treated effluent discharge: RPS 260

Updated 7 August 2025

Applies to England

This regulatory position statement (RPS) does not change your legal requirement to get an environmental permit for a waste operation when you use a nutrient treatment wetland (NTW) to improve the quality of treated final effluent discharged from a water and sewerage company waste water treatment works (WWTW).

However, the Environment Agency will not normally take enforcement action against you if you do not comply with this legal requirement 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

This RPS does not apply to water and sewerage companies.

This RPS is for parties other than water and sewerage companies who operate wetlands that receive treated final effluent discharged from water and sewerage company sewage treatment works.

Activity this RPS applies to

This RPS applies to surface flow NTWs with submerged and emergent vegetation where all the following apply:

• they provide further treatment to treated final effluent that has been discharged directly into the NTW from a water and sewerage company WWTW
• the discharge from the WWTW is authorised by an environmental permit
• the NTW is not operated by, or on behalf of, a water and sewerage company

Conditions you must comply with

Design and maintain your NTW

You must:

• ensure your NTW improves the quality of the final effluent received from the water and sewerage companies WWTW

• provide hydraulically efficient and effective treatment, avoiding preferential flow paths and ‘dead areas’ with limited throughflow

• follow Natural England’s ‘Wetland Mitigation Framework- Framework Approach for Responding to Wetland Mitigation Proposals’, if your NTW is to achieve nutrient neutrality

• plant a range of native submerged or emergent (or both) aquatic plants and manage these to maintain a healthy plant population

• manage and maintain your NTW over its design life and make sure you continue to meet these design and construction requirements

• have a written and agreed procedure with the water and sewerage company for operating the NTW – this must include procedures for communicating effectively on treatment, performance or operational incidents at either the WWTW or NTW that could result in harm to the environment

• have a decommissioning plan for your NTW, as described in Natural England’s Wetland Mitigation Framework

Protect surface water and groundwater

You must ensure the NTW:

• is not in hydraulic continuity with the local groundwater

• does not cause a deterioration in the quality of the receiving surface water or groundwater

You must construct the base and sides of your NTW with either a soil or a synthetic liner. The liner used must meet these permeability requirements:

• the base and sides of your NTW must have a low permeability, equivalent to or lower than 1x10^-7 metres per second, so that effluent does not infiltrate downwards into underlying groundwater at an unacceptable rate

• permeability testing of the liner must meet the standards in BS1377-6:1990 or to BS EN 1997-2:2007 and you must have analysis by a United Kingdom Accreditation Service (UKAS) accredited laboratory for the test – a civil engineer must confirm that you have placed any soil liner to the required permeability

Make sure your NTW does not impact conservation sites

You must ensure the construction of, and discharge from, the NTW does not cause either:

• adverse effects to designated conservation site or features
• damage to protected species or habitats

Conservation sites include:

• European sites (Special Areas of Conservation and Special Protection Areas)

• Ramsar sites

• Sites of Special Scientific Interest

• national and local nature reserves

Monitor your NTW

You must:

• take and analyse at least one spot sample a month of both effluent entering and leaving the NTW

• use a UKAS laboratory accredited for the tests to analyse the samples

• notify the Environment Agency by emailing WETProgramme@environment-agency.gov.uk with RPS 260 in the subject before you use this RPS

• 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 monitor the following water quality parameters in the samples:

• ATU-BOD as O₂ (the biochemical oxygen demand, measured after 5 days at 20⁰C with nitrification suppressed by the addition of allylthiourea) measured in mg/l
• ammoniacal nitrogen expressed as N measured in mg/l
• suspended solids measured after drying at 105°C measured in mg/l
• total phosphorus expressed as P measured in mg/l
• orthophosphate measured in mg/l
• total nitrogen expressed as N in mg/l
• nitrate expressed as N measured in mg/l
• temperature (°C)
• dissolved oxygen measured in mg/l

Things to note

Water and sewerage companies discharging into third-party NTWs have a duty of care to transfer waste to an authorised person. This RPS does not change this legal requirement. However, the Environment Agency will not normally take enforcement action against water and sewerage companies if the operator of the NTW receiving their wastewater discharge has notified the Environment Agency that they are using this RPS. 

When you must check back

The Environment Agency will review this RPS by 31 August 2027.

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.

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

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

If you cannot comply with this RPS

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

• stop the activity to which this RPS relates
• tell the Environment Agency immediately by emailing WETProgramme@environment-agency.gov.uk with RPS 260 in the subject

Contact the Environment Agency

If you have any questions about this RPS email WETProgramme@environment-agency.gov.uk with RPS 260 in the subject