WT2: Water Outflows/Discharges
Prefill
Eligible
Validation
Automatic; Evidence not validated
2026 Updates
None
Can the entity report on water outflows / discharges?
Water quality
Water outflows/discharges
External review
Has the data reported above been reviewed by an independent third party?
Assessment Instructions
Intent: What is the purpose of this indicator?
The intent of this indicator is to assess the entity’s measurement of water resource impacts. The inflow/withdrawal of water can have significant impacts on the environment and communities. Relatively high levels of water withdrawals can potentially create liabilities or regulatory risk.
Input: How do I complete this indicator?
Select Yes or No: If ‘Yes,’ complete the performance table and sub-questions.
Performance Tables
Cells with a dark green border are mandatory.
Cells with a light green shade are scored. Not all scored cells are mandatory. Leaving a scored (i.e., shaded) cell blank will have negative scoring impacts. ‘Zero’ is an acceptable answer if it is true and accurate (i.e., if no target exists, the cell should be left blank).
Data
Instructions
Performance: Previous Year
It is not possible to edit any data in this column.
As previous-year data is directly drawn from the previous year's Asset Assessment, it is not possible to amend erroneous data. If the previous-year data is incorrect (for example, a reporting error was made), the entity can use the open text box below the indicator to inform investors. This column shows the reported performance for the previous year (e.g. calendar year 2024). If a metric is new or has changed substantially compared to last year’s assessment, or if there is no data available for the entity for the previous year, it shows ‘N/A.'
Performance: Reporting Year
Enter data for performance during the reporting year for each metric.
Not scored but mandatory: Reporting year performance of third-party re-use, third-party treatment, and non-compliances.
Scored and mandatory*: Reporting year performance of 'Total discharge to sensitive waterways.'
*GRESB automatically calculates some metrics based on the inputs of other mandatory cells. If these cells show “NA”, it means that not all the values required for calculation have yet been provided.
The equations for the calculated cells are:
Total water discharged = Groundwate + “Seawater / brackish water + Surface water + Third-party re-use + Third-party treatment
Total discharge to sensitive waterways = Groundwater + Seawater / brackish water + Surface water
% recycled = Third-party re-use / Total water discharged * 100
See definitions for each metric in the Terminology section below.
Target: Reporting Year
Enter any targets that were applicable for the reporting year for each metric.
Scored but not mandatory: Reporting year target for 'Total discharge to sensitive waterways."
A reporting year target can be interpolated from a future-year target. The target (or the future-year target from which it is derived) must be formally adopted. This means that the entity must have set and communicated the target, at least internally, and implemented or is preparing actions to achieve it.
Target: Future Year
Enter the relevant year for which the targets are set at the top of the column and enter the future-year targets for each metric where available.
Scored but not mandatory: Future year target for "Total discharge to sensitive waterways"
The target must be set for any future year that is not the reporting year. The target (or the future-year target from which it is derived) must be formally adopted. This means that the entity must have set and communicated the target at least internally, and has implemented, or is preparing, actions to achieve the target.
Data Coverage (%): Reporting Year
Insert a data coverage level from 0% to 100% in single-digit increments for each metric where required.
Scored and mandatory: Reporting year performance data coverage for 'Total discharge to sensitive waterways'
Data coverage for any individual performance metric should represent an estimated percentage considering all material data related to all facilities and activities within the entity’s reporting boundary (RC3 and RC4) for the full reporting year.
Facility exclusions for data coverage: Facilities within an asset that have the following characteristics can be excluded in the reported data coverage levels:
Facilities under development.
Facilities that the asset has owned for less than 6 months.
Facilities that have been operational for less than 6 months.
Therefore, an asset can still report up to 100% data coverage for facilities even if it does not report data from facilities in the three categories noted above.
Note that if an asset reports less than 100% data coverage, its Benchmark Report will not display reporting-year performance data intensity values.
Data coverage calculation methodology
Provide a description of the method used to calculate data coverage in the open text box below the performance tables.
Not scored but mandatory: Data coverage methodology
In an open text box below the “Water outflows / discharges” performance table. provide description of the method used to calculate data coverage, including how the data was measured and how the coverage level was estimated or assessed (e.g. % coverage of facilities, output, GAV or any other metric used).
Water Quality
The volumes reported in the table “Water quality” should only reflect water discharged to natural bodies of water: groundwater, seawater / brackish water, and surface water. Entities should report by the quality of the water discharged, i.e., if 1000 ML of freshwater-quality water is discharged to ground and surface water, the entity should report 1000 ML under “freshwater.”
Intensities
It is not possible to edit any data in this section. GRESB automatically calculates intensity metrics based on data reported to other indicators.
If these cells show “NA”, it means that not all the values that are needed for calculation have yet been provided. The equations for the calculated cells are:
Water discharge intensity (/GAV) = Total water discharged / GA
GAV is reported in RC2 (Economic Size) and is converted from millions to units within the calculation.
Water discharge intensity (/Revenue) = Total water discharged / Revenue
Revenue is reported in RC2 (Economic Size) and is converted from millions to units within the calculation.
Water discharge intensity (/Output) = Total water discharged / Output
Output is reported in RC3 (Sector & geography) and is specific to the entity’s primary sector as reported in RC3.
Estimation Note
As a general rule, GRESB Participants are required to use actual data (i.e., directly measured from utilities or meters, documented, or derived using recognized standards) when reporting material performance data.
Broad extrapolations of data and general estimates should not be reported.
Participants must explain the methodology used to measure data and to calculate data coverage in an open text box below the performance table.
External Review
Select Yes or No: If selecting “Yes”, state whether the data submitted has been checked, verified or assured (select one option; the most detailed level of scrutiny to which the data was subjected). If selecting ‘verified’ or ‘assured,’ select the standard from the dropdown menu.
The Scheme Lists page contains the complete list of accepted assurance and verification schemes.
Additional assurance schemes may also receive recognition if they meet GRESB’s criteria. To submit a new scheme for review, please contact the GRESB team.
The final deadline for submitting a new assurance/verification scheme for review by the GRESB team is March 15th. Schemes submitted for review after March 15th will not be reviewed until the subsequent reporting year.
GRESB does not require the selected standard to be specific to water withdrawal data. A standard initially designed to verify/assure other types of sustainability data (e.g., energy) can be selected as long as the same thoroughness and review criteria are applied to data reported in WT2.
Terminology
Data Coverage
The part of the asset for which data is available. Data coverage represents an estimated percentage considering all material data related to all facilities and activities within the entity’s reporting boundary for the full reporting year.
Externally checked
Applies to instances when a third party has reviewed the data in a structured and consistent process, but no official certification has been awarded.
Externally verified
Applies to instances where a third party has reviewed the reporting against an existing scheme. When this checkbox is ticked, participants must select the scheme name from the dropdown.
Note that GRESB treats verification and assurance equally in the context of the assessment
Externally assured
Applies to instances where a third party has reviewed the data against an existing scheme. When this checkbox is ticked, participants should select the scheme name from the dropdown.
Note that GRESB treats verification and assurance equally in the context of the assessment
Freshwater (<1000 mg/L TDS)
Any water that contains less than 1000 mg per liter of total dissolved solids (TDS). This is a measure of water quality.
Groundwater
Freshwater that is found beneath the Earth's surface that supplies wells and springs.
Non-compliances
Failure to comply with covenants, environmental permits, laws and/or regulation due to the water outflows/discharges.
Other water (>1000 mg/L TDS)
Any water that contains more than 1000 mg per liter of total dissolved solids (TDS). This is a measure of water quality.
Potable water
Also known as drinking water. Potable water is any water that is safe for human consumption or food preparation.
Recycled water
Water that has been reused before discharge to final treatment or the environment. This can include water that was treated prior to reuse and water that was not treated prior to reuse. It can also include collected rainwater and wastewater generated by household processes such as washing dishes, laundry, and bathing (grey water).
Seawater/brackish water
Water obtained from seas, oceans or estuaries that has a salinity level of over 0.05%.
Surface water
Surface water is any freshwater occurring naturally on the Earth's surface, such as in lakes, rivers, ice sheets, glaciers or peatlands.
Third-party reuse
Reuse or recycling of water supplied by the Entity to a third party.
Third-party treatment
Treatment of municipal or industrial wastewater by a third party. The treatment can be primary, secondary or tertiary.
Water outflows/discharges
Discharge of water to water bodies (e.g. lakes, rivers, oceans, aquifers and groundwater) or to third-parties for treatment or use.
Validation: What evidence is required?
Data: GRESB automatically validates data in the performance tables.
Evidence: Providing evidence of external review in the form of a third-party letter or certificate is optional. Evidence will not be subject to manual validation for this indicator in 2025.
Evidence should include:
Proof of the existence of a third-party review of the data;
Clear indication that the reviewed data reflects the reported data;
A description of the type of third-party review (checked, verified, or assured) and the used assurance standard (if applicable);
Proof that the data review applies to the entity.
Scoring
Scoring: How does GRESB score this indicator?
Materiality-Based Scoring
The relevance of the 'Water outflow/discharges' issue (determined by the GRESB Materiality Assessment) defines this indicator's maximum score.
For more details, refer to the Asset Scoring Basics page or download the Asset Materiality & Scoring Tool.
Scoring of Metrics
The only scored metric for Water outflows/discharges is Total discharge to sensitive waterways.
For this metric, participants must complete all columns (Reporting-year performance, Reporting-year performance Data Coverage, Reporting-year target, and Future-year target) to obtain points as follows:
50% of the indicator score: based on a value reported for Reporting-year performance Data Coverage
The value reported for data coverage serves as a multiplier for the points available for this metric (i.e., only entities that report 100% receive the full scoring weight).
30% of the indicator score: based on the reporting of a value in Reporting-year performance
10% of the indicator score: based on the existence of a target in Reporting-year target
The scoring will be based on whether a target was set, not on whether the target was achieved.
10% of the indicator score will be based on the existence of a target in Future-year target
The scoring will be based on whether a target was set, not on whether the entity is on track to achieve the target.
Notes
Participants must input a target year under "Future-year target" as well as a numeric value in the underlying scored metric to score for this metric.
Not all scored cells/metrics are mandatory. If a scored (light green) cell is not outlined in dark green, leaving it blank will still result in a negative scoring impact. This applies to the following metrics: Total discharge to sensitive waterways: Reporting-year target; Future-year target.
Reporting of external data review is not scored.
Frequently Asked Questions
How should I calculate data coverage for performance data?
GRESB does not mandate a specific data coverage calculation methodology. Participants should report data coverage as an estimated percentage of the entity’s material facilities and activities within its reporting boundary (i.e. RC3 – Sector & Geography, and RC4 – Ancillary Activities) for which data was collected for the entire reporting year.
For indicator WT2 (Water outflows / discharge), what should I do if the entity has a discharge target in terms of pollution concentration and not volume?
GRESB has aligned WT2 with GRI Standards 2018 - 303-4: Water discharge. Reporting the total discharge is deemed more significant than reporting the water quality, and discharge quality standards are variable and based on local/organizational regulations. As such, participants should report the discharge volume based on the definitions in the indicator. An absolute discharge target may be derived from a quality target, if possible. An entity can use the open text box with the indicator to provide additional context to the reported targets and/or any discharge quality targets. Note that this text box is used for reporting purposes only and is not factored into scoring.
References
Eurostat - Environment Glossary
WRI - Aqueduct Water Risk Atlas
Alignment with External Frameworks
CDP Water Security 2021 - W1.2 Company-wide water accounting
CDP Water Security 2021 - W5 Facility-level accounting
CDP Water Security 2021 - W8 Targets
SAM Corporate Sustainability Assessment (CSA) - 4.1.6 EP - Water Consumption
GRI Standards 2018 - 303-4: Water discharge
Relevant UN Sustainable Development Goals
SDG 3 - Good Health and Well-being
3.9 By 2030, substantially reduce the number of deaths and illnesses from hazardous chemicals and air, water and soil pollution and contamination
SDG 6 - Clean Water and Sanitation
6.1 By 2030, achieve universal and equitable access to safe and affordable drinking water for all
6.3 By 2030, improve water quality by reducing pollution, eliminating dumping and minimizing release of hazardous chemicals and materials, halving the proportion of untreated wastewater and substantially increasing recycling and safe reuse globally
6.5 By 2030, implement integrated water resources management at all levels, including through transboundary cooperation as appropriate
https://sustainabledevelopment.un.org/sdg12
12.2 By 2030, achieve the sustainable management and efficient use of natural resources
12.4 By 2020, achieve the environmentally sound management of chemicals and all wastes throughout their life cycle, in accordance with agreed international frameworks, and significantly reduce their release to air, water and soil in order to minimize their adverse impacts on human health and the environment
14.1 By 2025, prevent and significantly reduce marine pollution of all kinds, in particular from land-based activities, including marine debris and nutrient pollution
Get Support: Solution Providers
GRESB Solution Providers are independent, third-party organizations within the GRESB Partner network that offer specialized products, tools, and services to support sustainability performance outside the GRESB Assessment process.
The organizations below deliver commercially available solutions designed to help drive improvement for this indicator. Engagement is managed directly between the reporting entity and the Solution Provider.
GRESB will continue to update this section as the GRESB Solution Provider network grows. Please check back regularly to find GRESB Solution Providers who can support your sustainability performance.
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