ISO/IEC 30134-9:2022

Overview

ISO/IEC 30134-9:2022 - Water Usage Effectiveness (WUE) defines a standard KPI for quantifying and reporting the water consumption of data centres during the use phase of their life cycle. WUE is a simple, comparable metric that expresses the water intensity of a data centre’s operations by relating water consumed to energy used by IT equipment. This part of the ISO/IEC 30134 series supports sustainability, resource-efficiency reporting and operational benchmarking across data centre facilities.

Key topics and technical requirements

• Definition of WUE: WUE is the ratio of data centre water consumption to the energy consumed by IT equipment (units relate water volume to IT energy).
• Measurement categories: The standard introduces WUE measurement categories and defines which water flows and boundaries apply when calculating WUE.
• Measurement and calculation: Rules for measuring actual water usage, selection of measurement period and reporting frequency are specified to ensure consistent, comparable results.
• Reporting requirements: A standard construct for communicating WUE data, mandatory data elements for public reporting, and recommendations for transparency.
• WUE derivatives: The standard covers derivative metrics such as interim WUE (iWUE), partial WUE (pWUE), design WUE (dWUE), quality WUE (qWUE) and peak WUE (peakWUE) for different use cases.
• Water reuse factor (WRF) and energy water intensity factor (EWIF): Methods to account for reused water and water used in energy production are included.
• Relationship to infrastructure and operations: Guidance on how WUE relates to cooling systems, IT equipment energy consumption and operational practices.
• Interpretation & context: Information on water significance, water stress, water quality and land consumption to help interpret WUE in geographical and environmental contexts.
• Normative references: Aligns with ISO/IEC 30134-1 (general KPI requirements) and ISO 8601-1 (date/time representation) for consistent reporting.

Applications and who uses it

• Data centre operators and facility managers use WUE to benchmark water intensity, track improvements in cooling systems and demonstrate resource stewardship.
• Sustainability and compliance teams incorporate WUE into environmental reporting and risk assessments (e.g., water stress evaluation).
• Design and engineering teams apply design WUE (dWUE) during planning to estimate operational water needs.
• Auditors, consultants and investors rely on standardized WUE reporting for due diligence, ESG assessments and facility comparisons.
• Regulators and policy makers can use WUE to inform water allocation and infrastructure resilience planning.

Related standards

• ISO/IEC 30134-1 - Overview and general requirements for data centre KPIs
• Other parts of the ISO/IEC 30134 series covering energy (PUE) and additional resource KPIs

Using ISO/IEC 30134-9:2022 enables consistent, transparent measurement and reporting of data centre water use, supporting operational optimization and sustainable data centre planning.