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Drainage and Wastewater Management Plans
English and Welsh water and wastewater companies (the companies) published their first Drainage and Wastewater Management Plans (DWMPs) in 2023. These plans established the levels of risk within their regions, how these risks are anticipated to change over the next 25 years due to factors such as climate change and growth, and how they plan to invest to mitigate these risks. Now, as part of a statutory requirement with newly published guidance, companies are already underway with the development of Cycle 2 of their DWMPs and will be looking to internally address the wide range of challenges they currently face, whilst continuing to operate in a rapidly changing environment.
Michael Smith
The original framework for DWMPs was published by Water UK in September 2018. Supported by a Steering Group that included representatives from regulators and water companies, the eleven England and Wales water and wastewater companies committed to producing DWMPs during AMP7 in accordance with the framework.
The framework stated that a DWMP will ‘set out how water and wastewater companies intend to extend, improve and maintain a robust and resilient drainage and wastewater system. The plan must take a long-term view, setting out a planning period that is appropriate to the risks faced by each company, but with a minimum period of 25 years.’
The aim was to improve and better align the long-term wastewater planning processes undertaken by water companies, whilst also improving collaboration and engagement with a wide range of stakeholders and increasing clarity on future investment decisions. DWMPs are expected to be integral to the development of water company business plans and provide a robust evidence base to the requirements outlined within them.
Cycle 1
After several published draft versions for consultation in 2022, the companies published their final DWMPs (DWMP24) in 2023. The plans are publicly available and detail the level of risk within each of their catchments for metrics including sewer flooding and storm overflow performance. They explain how those risks are predicted to change in both the short and long term due to factors such as population growth and climate change. The plans also detail the expected level of investment required in both PR24 and future price reviews to mitigate the identified risks. RPS provided support to United Utilities, Severn Trent Water, DCWW, Yorkshire Water and Anglian Water during the delivery of their first DWMPs.
Cycle 2
Whilst the companies were committed to producing DWMPs for Cycle 1, this was not a statutory requirement. However, following the commencement of section 79 of the Environment Act 2021, it became statutory for sewerage undertakers to prepare, publish, and maintain DWMPs, making the publication of Cycle 2 of the DWMPs a legal requirement.
As a statutory obligation, the Department for Food and Rural Affairs (Defra), rather than Water UK, adopted responsibility for detailing the requirements of DWMPs. Defra published guidance on the production of DWMPs on their website in May 2025, consisting of an introductory ‘About the guidance and planning for drainage and wastewater management’ page and a more comprehensive ‘How to form, publish and maintain your drainage and wastewater management plan (DWMP)’ page. This new guidance supersedes the previously published framework used for Cycle 1. referred plan.
The new guidance is less comprehensive than the previous framework but looks to build on learning from the completion of cycle 1, and also introduces several additional elements, broadening the potential remit of the DWMPs. It includes a mixture of ‘must’, ‘should’, and ‘could’ terminology to indicate which elements are legally required, which elements are strongly recommended, and which elements are optional but may strengthen the plan.
As shown in Figure 1, companies are expected to set the context of their DWMP at a regional level (Level 1), undertake an initial risk-based planning assessment to establish the level of detail required in subsequent risk and option assessments at the sewerage catchment level (Level 3), and then use a best value approach to develop a p
Significant variations in the new guidance include the requirement for receiving water quality assessments and associated modelling, additional water environment performance indicators (formerly Performance Objectives), a broader assessment of asset health focused within the risk-based planning stage, and an increased focus on combined risks with third parties. It is also now required that DWMPs be reviewed annually and updated as needed.
As with Cycle 1, ongoing and meaningful stakeholder engagement is expected throughout the development of the DWMP. The now statutory nature of DWMPs and subsequent introduction of statutory consultees may benefit the levels of engagement seen during future cycles of the DWMP.
What's next for DWMPs?
DWMPs are only one of several plans currently being developed by water companies, government, regulators, and other risk management authorities with a responsibility for drainage and the environment. These include the Water Industry National Environment Programme (WINEP), the Storm Overflow Discharge Reduction Plan (SODRP), River Basin Management Plans (RBMPs) and Pollution Incident Reduction Plans (PIRPs), amongst others. It is expected that DWMPs reflect and contribute to these other plans where inherently linked.
Companies are underway with the development of their next DWMPs, with draft publication expected by 1 November 2027, allowing for a 12-week public consultation. Final DWMPs are expected to be published by 31 August 2028. Future regulatory changes alongside updates to parallel plans, such as the 2027 review of the SODRP, will continue to influence Cycle 2 of DWMPs throughout their development.
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