SEOUL, South Korea, Feb. 16, 2026 /PRNewswire/ — As corporate commitments to environmental, social, and governance (ESG) goals reach an all-time high, a persistent blind spot remains: water. Long emphasized by Professor Yong Sik Ok of Korea University, who serves as President of the International ESG Association, water stewardship has lagged behind carbon emissions, which are now tracked with near-surgical precision. In contrast, corporate water management is often confined to vague qualitative disclosures and limited metrics.
To address this imbalance, a research team led by Prof. William Mitch of Stanford University and Prof. Ok of Korea University, in collaboration with Prof. Jay Hyuk Rhee of the Korea University Business School and the International ESG Association, has introduced a new framework to curb greenwashing in ESG reporting. Published in Nature Water on February 10, 2026, the study presents the Water Sustainability Index (WSI), a transparent, quantitative metric designed to strengthen corporate water accountability worldwide.
Prof. Mitch and Prof. Ok explained that the index shifts ESG water reporting from broad narratives to measurable and comparable outcomes, evaluating corporate water withdrawals, consumption, discharge quality, and reuse while accounting for local water scarcity to guide investments aligned with United Nations Sustainable Development Goal (SDG) 6.
The impetus for the WSI emerged from the stark data disparities in the London Stock Exchange Group database: while 14% of major companies reported greenhouse gas emissions, only 9% disclosed total water withdrawals, and just 1% reported recycled water use. “Water is fundamentally different from carbon,” Prof. Ok said. “While carbon is a global issue, water is intensely local, and ESG metrics must reflect that reality.”
Prof. Mitch and Prof. Ok emphasized that withdrawing a million gallons from a water-rich region differs vastly from withdrawing from a drought-prone basin. Existing ESG metrics often fail to capture this nuance with non-uniform and opaque algorithms, creating inconsistent assessments and unintentional “greenwashing.” The WSI moves beyond simple volume tracking, scoring source water type, watershed stress, discharge quality, consumption, and reuse.
Seven theoretical scenarios were evaluated to demonstrate the WSI’s effectiveness: a baseline stressed facility scored 1.17, rising to 1.98 with reuse and 3.0 maximized (with water quality upgrades and optimized siting). “The quantitative nature of the WSI allows companies to identify cost-effective pathways to improve water sustainability,” Prof. Mitch said. “It enables scenario testing before capital is committed.”
With 25% of the world’s population already living in extremely high-stress watersheds, the WSI bridges complex scientific frameworks such as ISO 14046 with the practical demands of ESG reporting, eliminating divergent ratings while advancing SDG 6.
Reference
Title of original paper: A quantitative metric for industrial water use sustainability for environmental, social and governance reporting
Journal: Nature Water
DOI: 10.1038/s44221-025-00575-9
Media Contact:
International ESG Association
Yong Sik Oh
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SOURCE International ESG Association
