HWMI was first published in September 2016 and revised as v1.1 in June 2020. It enables hotels to consistently measure and report water withdrawal. HWMI v2.0 is a consultation draft that proposes to formalise HWMI from a guidance tool into a methodology standard, with expanded water sources, improved data quality requirements, and enhanced audit-readiness to support future assurance arrangements.
HWMI v2.0 is transitioning from a guidance tool into a methodology standard with clear scope, boundaries, definitions, data requirements, calculation rules, and version control under a structured review cycle.
The methodology now accounts for additional water sources, including metered and unmetered municipal water, delivered water (including recycled water from external sources), onsite desalinated water, rainwater, ground/surface water, and other water sources, enabling hotels to capture a more comprehensive view of their water withdrawal.
Hotels can now record the quantity of water recycled or reused on-site to highlight progress in water conservation. Recycled/reused water remains excluded from the intensity metrics.
Introduces a recommended WRI Aqueduct Baseline Water Stress calculation (annual, Water Stress indicator) to provide location context. The water stress value is displayed alongside results and is not incorporated into the intensity metrics.
Hotels with sub-metered water data are encouraged to input specific measurements to improve tracking of main water uses on-site and reduce reliance on estimation.
The methodology includes guidance on accounting for water withdrawal from third-party laundry services and the option to separate out laundry done on-site for third parties.
Output metrics now are calculated both per occupied room-night and per guest-night to align with WSHA’s Universal Sustainability KPIs. Occupied room-night continues to be the standard external reporting denominator.
The standard’s language, definitions, and data requirements have been strengthened to support future assurance and verification arrangements, subject to WSHA’s published assurance system when available. Data quality checks — including the share of water withdrawal derived from estimated data and outlier checks against benchmarks — further support audit-readiness. Until the assurance system is published and effective, results should be treated as self-reported and unassured.
We invite all stakeholders to review the draft standard and share feedback via the survey below. The survey covers topics including new water sources, data quality, calculation consistency, and auditability. Multiple submissions per organisation are welcome.