WT1: Water Consumption
Assessment Instructions
Participants must report this metric at the asset level.
GRESB automatically populates this indicator in the assessment response once participants have aggregated asset-level data from the Asset Portal.
When using the Asset Spreadsheet to upload asset-level data, GRESB recommends reviewing the instructions below in conjunction with the corresponding spreadsheet tab. The Cell Code column in the Input section indicates where to report each metric in the spreadsheet.
Asset Portal Guide Click here to download a read-only version of the Asset Spreadsheet.
Consumption (m3)
Floor Area Covered (m2/ sq ft)
Maximum Floor Area (m2/ sq ft)
Shared services / Common areas
Consumption (m3)
Floor Area Covered (m2/ sq ft)
Maximum Floor Area (m2/ sq ft)
Tenant Spaces - Landlord Controlled / Tenant Spaces - Tenant Controlled
Consumption (m3)
Floor Area Covered (m2/ sq ft)
Maximum Floor Area (m2/ sq ft)
Input: How do I complete this metric?
Which floor area breakdown (i.e., reporting level) is appropriate?
Report at the Whole Building level when separate data for base building (i.e., common areas and shared services) and tenant space is unavailable.
Report at the Base Building & Tenant Space level when separate data for base building (i.e., common areas and shared services) and tenant space is available.
The reporting level for water does not need to match the reporting method chosen in the energy section.
Data
Cell Code
Instructions
Consumption (m3)
G7 L7 M7 P7 S7
Report two consecutive years of water consumption.
Consumption Value: Participants must report known absolute water consumption for a given space, regardless of the % of ownership. If the area is supplied by utilities but consumption is unknown, leave this field empty. See examples below.
Estimation: Participants must use actual data (non-estimated). However, GRESB allows asset-level estimates under specific conditions outlined in the Data Quality & Validation page when actual data is partially unavailable.
Outdoor: Only include the energy consumption of outdoor/exterior/parking areas in the whole-building energy consumption if it is metered together with the rest of the asset.
Shared Services & Common Areas
J4-O4
If an asset's Base Building consumption data comes exclusively from Shared Services, it is still mandatory to provide a floor area size for Common Areas.
However, if the consumption of Common Areas cannot be separated from Shared Services and is fully included in Shared Services, the Data Coverage for Common Areas should be equal to the coverage reported under Shared Services. See examples below.
Floor Area Covered (m2/sq.ft.)
K7/N7/Q7/T7
This refers to the floor area corresponding to the reported consumption.
If consumption is unknown, enter 0 for the floor area covered.
Max Floor Area (m2/sq.ft.)
L7/O7/R7/U7
This refers to the total floor area serviced by the reported utility type.
If the consumption is not known for the entire area, the maximum floor area may differ from the floor area covered. The sum of the Base Building + Tenant Spaces floor area should be greater than or equal to the asset size.
Examples
General Data Coverage
Example 1: The area is supplied with water, but the consumption data is unknown to the participant.
0
10,000
Example 2: The area is supplied with water, and the participant knows that there was no consumption during the entire reported period
0
10,000
10,000
Example 3: The area is supplied with water, but the participant only knows 75% of the total consumption during the entire reporting year
12,500
7,500
10,000
Example 4: The area is not supplied with water
For floor areas not serviced by a utility, all 3 fields are to remain empty.
Common Area & Shared Services Data Coverage
Scenario A: The Base Building of an asset is composed of Common Areas (2,000 sqm) and Shared Services (10,000 sqm). Consumption cannot be separated between Common Areas and Shared Services - the entire consumption is tracked together. By definition, Shared Services overlap with the Common Areas. The entity knows the total water consumption of Base Building (2500 m3), and reports it under Shared Services as:
Water
2500
10000
10000
The resulting Data Coverage for Shared Services is [Floor Area Covered / Maximum Floor Area] = [10,000 / 10,000] = 100%.
It is mandatory to also provide a maximum floor area of the Common Area. If the Base Building consumption consists only of Shared Services, the asset's Common Area data coverage should equal that of Shared Services. As explained above, participants must also include a value in the Common Areas section.
Given that the consumption value relating to the entire Base Building has already been reported through Shared Services, any remaining consumption specific to Common Areas should be zero.
Water
0
2000
2000
Reporting water consumption this way means that, while the area was supplied with water, the participant knows that consumption is zero.
The resulting Data Coverage for Common Areas is [Floor Area Covered / Maximum Floor Area] = [2,000 / 2,000] = 100%.
At the Base Building level, the aggregated Data Coverage would equal the weighted-average Data Coverage of both Shared Services and Common areas, respectively:
100%*[10,000 / 12,000] + 100%*[2,000 / 12,000] = 100%
The final result of 100% is correct because the participant knows all consumption values associated with an asset’s Base Building.
Scenario B: The Base Building of an asset is composed of Common Areas (2,000 sqm) and Shared Services (10,000 sqm). Common Areas and Shared Services consumption is tracked separately. The consumption for the Shared Services is 2,500 m3, and the consumption for the Common Areas is unknown.
If the entity only has data for Shared Services and does not capture Common Areas consumption, the Common Area coverage should be zero, while the Shared Services coverage should be 100% as per the example below.
Water
0
2000
Water
2500
10000
10000
Reporting in this manner means that while the area is supplied with water, the consumption is unknown to the participant.
The resulting Data Coverage for Common Areas is:
[Floor Area Covered / Maximum Floor Area] = [0 / 2,000] = 0%.
At the Base Building level, the aggregated Data Coverage would equal the weighted-average Data Coverage of both Shared Services and Common areas, respectively:
100%*[10,000 / 12,000] + 0%*[ 2,000 / 12,000] = 83.3%
Validation: What evidence is required?
This indicator is subject to automatic validation. No evidence is required. Refer to the page below for guidance on how to resolve automatic validation errors and warnings. Validation Basics
Scoring
Operational water consumption influences data coverage (4 points total) and like-for-like performance (2 points total) score calculation.
Data Coverage
Step 1: Calculate Asset-Level Data Coverage
GRESB calculates each asset's percentage of data coverage based on both area and time for which data is available — separately for landlord and tenant-controlled areas:
Landlord-controlled areas include Whole Building: Landlord-Controlled, Base Building (Shared Services and Common Areas), and Tenant Spaces: Landlord Controlled.
Tenant-controlled areas include Whole Building: Tenant-Controlled and Tenant Spaces: Tenant Controlled.
Step 2: Score Each Asset
GRESB compares asset-level data coverage against a relevant benchmark distribution based on the same property sub-type and country, and specific to landlord-controlled and tenant-controlled areas. In other words, each control type earns its own score.
If the asset reports at the Base Building + Tenant Space Level:
GRESB further aggregates the control-type scores based on its floor area weight within the asset. Base Building data coverage holds a 40% weight, and Tenant Space data coverage holds a 60% weight.
Since tenant spaces can include both landlord-controlled and tenant-controlled areas, the 60% weight is further distributed based on the floor area for each. Specifically:
Landlord-controlled space scores are calculated as:
40% + 60% * Tenant Spaces landlord-controlled area proportion (%)
Tenant-controlled space scores are calculated as:
60% * Tenant Spaces tenant-controlled area proportion (%)
If the asset reports at the Whole Building level, the aggregation steps above do not apply.
How does GRESB construct benchmarks used for scoring?
First, an attempt is made to construct a benchmark by grouping values from assets with the same Property Sub-Type and located in the same Country. If there are not at least 20 values from 5 distinct reporting entities, the Property Sub-Type classification and then the Country specificity are gradually decreased.
For example, the Property Sub-Type becomes Property Type and then Property Sector. Then the specificity of the Country is decreased to Sub-Region, Region, Super-Region, and Global.
Step 3: Aggregate to the Property Subtype | Country Level
GRESB aggregates the asset-level scores to each property sub-type and country combination, using a weighted mean calculated by multiplying floor area by the percentage of ownership and the length of ownership period in the reporting year.
Step 4: Aggregate to the Portfolio Level
The scores for each property sub-type and country are aggregated into a single portfolio score, weighted by the gross asset value (GAV) for each property sub-type and country.
Like-for-Like Performance Improvement
Step 1: Determine Asset-Level Like-for-Like (LFL) Eligibility
Only space(s) within assets that meet all the following criteria, for both current and previous reporting years, are eligible for inclusion in the like-for-like calculations:
Data Availability covers the full year (> 355 days);
Data Coverage is positive
Data Coverage is the same (within 1% error threshold);
The asset is classified as a Standing Investment.
Assets that lack LFL-eligible space are excluded from the aggregation and do not negatively impact the entity’s score.
If no asset within a property sub-type and country group meets the like-for-like data availability criteria, all assets in the group receive a score of zero for like-for-like.
Step 2: Score Each Asset's LFL Improvement
GRESB compares the % LFL change of each eligible asset space against a relevant benchmark distribution based on the same property sub-type and country, and specific to landlord-controlled and tenant-controlled areas. In other words, each control type earns its own score.
If the asset reports at the Base Building + Tenant Space Level:
GRESB further aggregates the control-type scores based on its floor area weight within the asset. Base Building data coverage holds a 40% weight, and Tenant Space data coverage holds a 60% weight.
Since tenant spaces can include both landlord-controlled and tenant-controlled areas, the 60% weight is further distributed based on the floor area for each. Specifically:
Landlord-controlled space scores are calculated as:
40% + 60% * Tenant Spaces landlord-controlled area proportion (%)
Tenant-controlled space scores are calculated as:
60% * Tenant Spaces tenant-controlled area proportion (%)
If the asset reports at the Whole Building level, the aggregation steps above do not apply.
Step 3: Aggregate to the Property Subtype | Country Level
GRESB aggregates the asset-level scores to each property sub-type and country combination, using a weighted mean calculated by multiplying floor area by the percentage of ownership and the length of ownership period in the reporting year.
Step 4: Aggregate to the Portfolio Level
GRESB aggregates the scores for each property sub-type and country into a single portfolio score, weighted by the gross asset value (GAV) for each property sub-type and country.
Frequently Asked Questions
How does GRESB construct the benchmarks used to score performance metrics?
First, an attempt is made to construct a benchmark by grouping values from assets with the same Property Sub-Type and located in the same Country. If there are not at least 20 values from 5 distinct reporting entities, the Property Sub-Type classification and then the Country specificity are gradually decreased.
For example, the Property Sub-Type becomes Property Type and then Property Sector. Then the specificity of the Country is decreased to Sub-Region, Region, Super-Region, and Global.
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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