Stage 0: Before you begin

This toolbox is not official EU guidance. The IUWMP Journey presented in this Toolbox was developed by seecon within the WATERUN project. It offers one way of translating the Annex V requirements into a coherent planning process. The guide walks you through the four stages of preparing an IUWMP, from understanding your system to monitoring results.

It draws on:

• The Directive and Annex V themselves, which define the mandatory content of an IUWMP.
• Established urban drainage planning practice, in particular the SuDS Manual (WOODS BALLARD et al. 2015), the source–pathway–receptor framing, and risk-based catchment planning as practised under the Water Framework Directive.
• Existing drainage and wastewater planning frameworks from comparable jurisdictions, that provide practical precedents for each of the stages 1–4, such as:
  • VSA Leitfaden GEP 2025 and Basel GEP (REGIERUNGSRAT BASEL-STADT 2012) in Switzerland,
  • Statutory DWMP guidelines (DEFRA et al. 2025) and WFD risk assessment methodology (ENVIRONMENT AGENCY 2017) in the UK,
  • France’s Plan d’action eaux pluviales (Ministère de la Transition écologique 2021),
  • CSO planning guidance from the US EPA (1995) and MAINE DEP (1994).
• Relevant literature on stormwater pollution, nature-based solutions, and urban runoff modelling.

EU Directive 2024/3019 requires Integrated Urban Wastewater Management Plans (IUWMPs) for agglomerations of 100,000 p.e. and above by 31 December 2033, and for smaller agglomerations (10,000–100,000 p.e.) where stormwater poses identified risks, by 31 December 2039 (EUROPEAN PARLIAMENT & COUNCIL OF THE EU, 2024; hereafter Directive (EU) 2024/3019). The Directive sets a headline target: stormwater overflow should represent no more than 2% of your city’s annual dry-weather wastewater load, measured using BOD₅, COD, TOC and TSS (Directive (EU) 2024/3019).

Annex V sets out what the plan must contain, but the detailed methodology is still being worked out: the Commission's technical guidance is not expected before January 2028, and national rules will follow after that.

The four stages translate this into actionable plans:

Figure 1: Overview of the IUWMP Stages. Source: OWN ELABORATION ( 2026)

The process is iterative. You may find that Stage 1 reveals data gaps that prevent you from setting credible targets in Stage 2. That is normal. Go back, fill the gaps, and continue.

How can I prepare for an effective IUWMP process? There are a few things to sort out before you start the technical work to prepare your IUWMP. The first three aim to set up your team and the last three to anchor your plan in the wider institutional landscape.

Who leads? Clarify who coordinates the IUWMP, who contributes data, and who formally approves the plan. This varies: it may be a municipal department, a utility, or a shared arrangement.

How will data flow? Poor data exchange between departments is consistently the main non-technical barrier. Agree on formats, responsibilities, and handover protocols before you start.

Who needs to be involved? Set up a standing stakeholder group with environmental agencies, operators, urban planning, roads and transport. You will need their input at every stage, not just at the beginning. Include departments not traditionally part of water management: urban planning, roads, parks and green spaces. Engagement is not a one-off consultation. Key decisions on which areas to prioritise, what risk is acceptable, which measures to implement all benefit from input by the people affected, the people implementing, and the people who will maintain the infrastructure.

Tackle organisational barriers early. Across cities and planning traditions, the main barriers are organisational: fragmented governance, inertia, staff turnover (STOPUP CONSORTIUM 2025). Address these at the start, not as an afterthought.

Connect to other municipal plans. The IUWMP does not exist in isolation. Link it to spatial planning, climate adaptation, flood risk management, biodiversity strategies, transport plans, and the WFD river basin management plan (EUROPEAN PARLIAMENT & COUNCIL OF THE EU 2000; EC 2021; DEMUZERE et al. 2014). Aim for it to become a binding planning instrument, not a document that sits on a shelf (REGIERUNGSRAT BASEL-STADT 2012).

Plan for institutional continuity. Urban water systems become visible mainly upon failure. Stakeholder engagement is easiest after a crisis but keeping it going requires deliberate effort. Document your decisions and their rationale. Make sure knowledge transfer survives staff changes.

----> You can directly continue to Stage 1 of the IUWMP Journey or go back to Resume. <----