ISO 24566-4:2025

Overview

ISO 24566-4:2025 - "Drinking water, wastewater and stormwater systems and services - Adaptation of water services to climate change impacts - Part 4: Wastewater services" provides guidance and requirements for identifying and assessing climate change impacts on wastewater systems and for developing adaptation strategies. The standard applies to both combined and non-combined wastewater systems covering collection, transport, storage and treatment activities and builds on the assessment principles in ISO 24566-1.

Key topics and technical requirements

ISO 24566-4:2025 organizes practical requirements and guidance around systematic assessment and strategy development. Core topics include:

• Assessment methodology
  • Principles and steps for assessing current and future climate-related hazards and exposures.
  • Identification of key functions and typical assets of wastewater systems (collection, transport, storage, treatment).
• Vulnerability and risk assessment
  • Procedures for identifying system vulnerabilities across governance, operation, asset management, risk management, metrics and targets.
  • Assessment of current climate-related hazards and projected future hazards.
• Adaptation strategy development
  • Guidance on formulating, categorizing and prioritizing adaptation responses and actions.
  • Use of assessment protocols, templates for response options, and examples of implemented responses.
• Financial assessments
  • Considerations for financing adaptation, cost–benefit analysis and evaluating economic feasibility.
• Implementation and monitoring
  • Requirements for implementation planning, monitoring, review and iterative updates of adaptation measures.
• Supporting elements
  • Governance, metrics and targets, operational resilience, and asset-management integration.

Practical applications and users

ISO 24566-4:2025 is intended for stakeholders responsible for wastewater services who need to integrate climate resilience into planning and operations:

• Municipal water and wastewater utilities adopting climate adaptation strategies for collection and treatment systems.
• Asset managers and engineers conducting vulnerability assessments and updating asset-management plans.
• Risk and emergency planners who evaluate climate-related hazards (e.g., increased flooding, sea-level rise, extreme rainfall).
• Policy makers and regulators setting requirements or guidance for municipal infrastructure resilience.
• Consultants and financial planners performing cost–benefit analyses and designing financing approaches for adaptation investments.

Practical uses include developing adaptation plans, prioritizing resilience investments, preparing operational response protocols, and documenting governance and performance metrics.

Related standards

• ISO 24566-1 - Assessment principles for adaptation of water services to climate change.
• ISO 24513 - Vocabulary for service activities relating to drinking water, wastewater and stormwater systems.
• Other parts of the ISO 24566 series for drinking water and stormwater adaptation guidance.

Keywords: ISO 24566-4:2025, climate change adaptation, wastewater services, vulnerability assessment, asset management, municipal wastewater, combined sewer, adaptation strategy, financial assessment, risk management.