ESG and water management: the 5 GRI water indicators and how to prove results
In ESG, water is one of the most concrete topics in the E: it can be measured, reduced and proven. See what ESG is, the 5 water indicators of GRI 303, how to set targets and how to turn water savings into verifiable data in the report.
By T&D Sustentável 7 min read
In this article · 8
ESG stands for environmental, social and governance, the three groups of criteria that investors, clients and regulators use to assess how a company handles risks and impacts beyond its financial results. Water sits mainly in the E and is one of the most concrete topics on the agenda: it can be measured, reduced and proven. In a sustainability report, the most widely used standard for it is GRI 303, which asks how the company withdraws, consumes and discharges water.
In short:
- The term ESG took shape with the Who Cares Wins report of 2004, by the UN Global Compact with financial institutions.
- On water, the E covers consumption, losses and effluent; the S, community access and health; the G, targets, owners and accountability.
- GRI 303 has 5 indicators: interactions with water as a shared resource, management of discharge-related impacts, withdrawal, discharge and consumption.
- A water target that holds up has a baseline, a per-unit indicator, a deadline and an owner.
- A result that counts in the report is measured, ideally under a protocol such as IPMVP. Rede D’Or published a 16.5% cut in consumption across 40 hospitals in its GRI report.
What is ESG?
ESG brings together three groups of criteria. Environmental covers climate, water, waste, pollution and biodiversity. Social covers relations with employees, customers, suppliers and communities, from human rights to health and safety. Governance covers how the company is run: board, audit, ethics, whistleblowing channels and accountability.
The term took shape in 2004 with the Who Cares Wins report, by the UN Global Compact, which proposed that financial institutions bring these three topics into risk and investment analysis. Since then, the acronym has moved beyond the financial market into companies’ contracts, purchasing and reports.
ESG and sustainability go together but are not synonyms. Sustainability is the broad goal; ESG is the way to measure and report performance on each topic, with indicators a third party can compare and verify.
Where does water fit in ESG?
In all three pillars, with different indicators in each:
| Pillar | What water represents | Examples of what to measure |
|---|---|---|
| Environmental | The use of a limited resource and the impact of effluent | Withdrawal, consumption, losses, effluent volume and quality, reuse |
| Social | The operation’s effect on the water of those living around it | Competition for water in the basin, quality of what returns to the river, community access |
| Governance | How the company decides and reports on water | Approved targets, owners, audited figures, compliance with permits and licences |
The weight of water changes with the sector and the location. For a hospital, a hotel or a food manufacturer, it is a critical operating input; in a water-stressed basin, it is also a continuity risk and a matter of community relations.
What are the GRI 303 water indicators?
GRI 303, the Water and Effluents standard of the Global Reporting Initiative published in 2018, organises the topic into five indicators. The first two describe management; the last three, volumes, reported in megalitres (1 megalitre is 1,000 m³):
| Indicator | What it asks for | Where the data comes from |
|---|---|---|
| 303-1 Interactions with water as a shared resource | How the company withdraws, consumes and discharges water, what impacts that creates and how it addresses them with stakeholders | A map of the uses, sources and effluent of each site |
| 303-2 Management of water discharge-related impacts | The minimum standards for effluent quality and how they were set | Environmental licence, discharge permit, lab reports |
| 303-3 Water withdrawal | The volume withdrawn, by source type, including in areas with water stress | Utility invoices, well and abstraction meters |
| 303-4 Water discharge | The volume discharged, by destination | Effluent meters, sewage bills |
| 303-5 Water consumption | Total water consumption, including in areas with water stress | The difference between withdrawal and discharge, backed by metering |
Most reports are weakest in the third column: when the data comes only from the monthly invoice, with no metering by site and by area, the number exists but explains nothing. Metering is what shows where the water went and what changed.
How do you set water targets for ESG?
A water target that survives the auditor’s first question has five elements:
- Baseline. Twelve to twenty-four months of consumption, by site, with the variables that explain it: occupancy, production, weather.
- Intensity indicator. Consumption per bed, per meal, per tonne produced or per square metre, so that the company’s growth neither hides efficiency nor invents it.
- Deadline and goal. How much to cut and by when, in volume and in intensity.
- Plan. The fronts that deliver the reduction: leaks, equipment, processes, reuse.
- Owner and review. Who answers for the target and how often the result is reviewed.
The step by step of the reduction fronts is in the guide to water savings for businesses.
How do you prove water results in the report?
Water savings are water that was not consumed, so they cannot be measured directly: they are the difference between actual consumption and what the company would have consumed without the programme, under the same conditions. The international IPMVP protocol solves this with a baseline adjusted for the variables that changed. At T&D, the statistical baseline is built from the site’s consumption history and adjusted by multivariate regression, which makes the result auditable.
The strongest example comes from a third party’s report. At Rede D’Or, T&D’s water efficiency project cut consumption by 16.5% across the 40 hospitals served, saving 260,000 m³ of water in 2025, and the result was published in the network’s sustainability report under the GRI standard. The full case is in the Rede D’Or case: 16.5% less water in 40 hospitals.
For a company that wants to run its own water management all the way to the report, T&D’s HydroDesk combines technology bought by the company, staff training and remote consulting, in a four-phase journey that reaches GRI preparation and SDG mapping. In SEA 360º, ongoing management includes monthly reports on financial, operational and ESG performance.
Water footprint and SDG 6: where do they fit?
They are two lenses that complement GRI. The water footprint adds up the water used directly and indirectly to make a product, including in the supply chain; it explains why a product carries far more water than the bill shows. The topic is covered in virtual water. SDG 6, the UN Sustainable Development Goal on clean water and sanitation, gives the global context into which a company’s water targets fit. See the four UN goals a water programme touches.
Frequently asked questions
What is the difference between ESG and sustainability?
Sustainability is the broad goal of operating without compromising the future of the environment and people. ESG is the way to measure and report that performance across three pillars, environmental, social and governance, with comparable indicators that investors, clients and auditors can verify.
What is GRI 303?
It is the Water and Effluents standard of the Global Reporting Initiative, published in 2018 and used in sustainability reports. It has five indicators: interactions with water as a shared resource, management of discharge-related impacts, withdrawal, discharge and consumption, with volumes reported in megalitres.
How do you measure water for a sustainability report?
Start with the invoices and the meters of each source, such as the water utility and wells, and add them up by site. To explain the number, meter by area and follow consumption frequently: that is what shows where the water went and what the reduction changed. One megalitre is 1,000 m³.
What is water stress?
It is the situation of a region where demand for water presses on availability, with a risk of shortage for the basin’s uses. GRI asks companies to highlight withdrawal and consumption in those areas, and public tools, such as the World Resources Institute’s Aqueduct, help identify them.
Where do you start with water management for ESG?
With the baseline and metering: twelve months of consumption by site, intensity indicators and a leak test. Then come the targets, the reduction plan and the report. The full path is in the guide to water savings for businesses.
Sources
- B3 Bora Investir, report on the origin of ESG, in Portuguese: the Who Cares Wins report of 2004
- GRI 303: Water and Effluents 2018 (Global Reporting Initiative)
- GRI 303, presentation of the 2018 standard (Global Reporting Initiative)
- IPMVP Core Concepts, Efficiency Valuation Organization (EVO)
- The Rede D’Or case: 16.5% less water in 40 hospitals, with figures from the network’s sustainability report (GRI standard, 2025)
- T&D HydroDesk and SEA 360º
