Last updated
Last updated
Water has a vital role in ensuring a sustainable and equitable future of real estate. To identify opportunities for water conservation with the greatest potential impact across a portfolio, it is essential to understand a portfolio's total water use, and water use intensity. Properties within a portfolio with high water use will face increasing financial risks, including higher operating costs, and exposure to service disruptions and fluctuating water prices. Efficient management of water use is critical to mitigating rising costs and risks.
Investing in water-efficient technologies positions a portfolio to face increasingly stringent regulatory landscapes while enhancing property value and increasing competitiveness. Investments related to water can help organizations contribute to universal access to safe drinking water, protecting the natural environment and advancing water conservation strategies.
There are two metrics available in the “Water” category:
To reduce water consumption, to source non-potable water, and to preserve no- and low-cost water resources.
Total Water Use
The volume of water consumed by all properties in a portfolio over a specific period. Total Water Use includes potable and non-potable water used for both indoor and outdoor purposes like drinking, irrigation, cooling, sanitation etc.
Water Use Intensity (WUI)
Water consumption by the portfolio per unit of floor area, excluding parking, over a specific period. WUI may be expressed as indoor WUI, which includes only indoor water use, or general WUI, which includes both indoor and outdoor water use.
Total Water Use
Gallons (gal), cubic feet (cu ft), centum cubic feet (CCF), liters (L), cubic meters (cu m)
Water Use Intensity
WUI is expressed in units of volume of water use (e.g., gallons, liters, etc.) per unit floor area (e.g., sq ft, sq m, etc.)
Total Water Use
Performance Approach A (absolute performance): Verification of Total Water Use across the defined portfolio for the reporting year.
Performance Approach B (performance change): Verification of the change in Total Water Use from a baseline year across the defined portfolio.
Water Use Intensity
Performance Approach A (absolute performance): Verification of indoor WUI or general WUI across the defined portfolio for the reporting year.
Performance Approach B (performance change): Verification of the change in indoor WUI or general WUI from a baseline year across the defined portfolio.
Total Water Use
Provide Total Water Use for all properties in the defined portfolio for the reporting year (Performance Approach A) and/or baseline year and reporting year (Performance Approach B). Describe methodologies, standards, frameworks or tools used to determine Total Water Use, if applicable.
Include both potable and non-potable water sources in the Total Water Use data for each property.
Use actual water use data, utilizing source water meters and/or utility bills, from every month for each property to determine Total Water Use for the reporting year.
If estimates are used for unmetered sources of water (e.g., potable, non-potable and alternative water sources collected on-site), an explanation of the methodology used to obtain these estimates must be provided.
Water Use Intensity
In addition to the above requirements, provide the total gross floor area for the portfolio excluding parking for the applicable years. Organizations may choose to report WUI as indoor WUI, which includes only indoor water use, or general WUI, which includes both indoor and outdoor water use.
Portfolio-Level Documents:
Policies: If applicable, provide documentation (e.g., policies, narratives, reports, letter from CEO, etc.) indicating the organization’s commitment to water use reduction including specific targets and goals set.
Methodology: Provide documentation describing the data collection methods used to determine water use, including:
Estimations and calculations that were used when accurate data was not available (e.g., for alternative water sources). When available, detailed whole-building metering data is preferred.
Templates used to complete the tracking in a consistent manner.
For Performance Approach B only, provide documentation that summarizes the baseline year, including:
Reporting period for the baseline year.
Methods for determining the selected baseline year.
Letter of attestation from senior/executive leadership or the individual/entity calculating the water use confirming that the baseline year data was calculated in a similar manner as the reporting year OR third-party verification of baseline year data. If baseline year data was previously verified by GBCI, this evidence is not required.
Plans and Actions: If applicable, provide documentation describing plans the organization has in place that assisted in achieving the target and actions or strategies implemented to achieve water use reduction.
Property-Level Documents:
Property-Level Data: Utilizing the PERFORM Property-Level Data Form, provide Total Water Use data and, for WUI, provide the gross floor area excluding parking for every property for the reporting year (Performance Approach A) and baseline year and reporting year (Performance Approach B). Provide both indoor and outdoor water use for general WUI and only indoor water use for indoor WUI. Alternative documentation (e.g., spreadsheets prepared for other reporting entities or internal tracking sheets, etc.) may be provided if it has the same information as the PERFORM Property-Level Data Form.
Property-Level Sample Documents: Provide the following documentation for a sample of SQRT(n) properties, where ‘n’ is the total number of properties in the portfolio. A list of properties selected for sampling will be provided during the portfolio creation process via the Multiple Property Upload Template.
Spreadsheets with at least twelve months of continuous water use data for the sampled property for the reporting period.
Descriptions of all water sources used at the sampled property, including alternative water sources. Alternative water sources may include reclaimed wastewater (e.g., municipally supplied or treated on-site), greywater, harvested rainwater or stormwater, captured condensate from air-handling units, treated seawater condensate, reverse osmosis reject water, used process water and foundation dewatering water.
Utility bills that report water usage or a sample of detailed meter readings for the water demands. Usage values and dates must be highlighted.
Third-party data assurance or audit reports and documents, if applicable.
Water Use Intensity:
Water Use Intensity (WUI) measures how efficiently water is used in a portfolio by calculating the water consumption per unit of floor area over a specific period. This is calculated by dividing the total water use for the portfolio with the total floor area of the portfolio excluding parking to determine WUI/year. If calculating indoor WUI, exclude outdoor water use. If calculating general WUI, include outdoor water use.
Performance Change in Water Use or Water Use Intensity:
Performance change between the reporting year and a baseline year is calculated for this metric using the percentage change formula:
REFERENCES
BREEAM In-Use International: Technical Manual – Commercial: Management Performance – Wat 14 Water Strategy
TERMINOLOGY
Baseline Year: A specific year (12-month period) used to track changes in performance over time.
Indoor Water Use: Water used inside the building for activities such as drinking, cleaning, cooking, sanitation, cooling tower, etc.
Non-Potable Water: Water that is not treated to drinking water standards and is not meant for human consumption.
On-site Alternative Water: Water captured on-site, including reclaimed wastewater (e.g., municipally supplied or treated on-site), greywater, harvested rainwater or stormwater, captured condensate from air-handling units, treated seawater condensate, reverse osmosis reject water, used process water and foundation dewatering water.
Outdoor Water Use: Water used on site outside the building for activities such as irrigation, swimming pools, landscape features etc.
Potable Water: Treated water that is safe for human consumption.
Reclaimed Water: Wastewater that has been treated for reuse.
Water Consumption: The portion of water use that is not returned to the original water source after being withdrawn.
Water Use: The amount of water withdrawn from its source to be used across a portfolio.
Water Use Intensity: A property’s or portfolio’s water use as a function of its size (by unit floor area).
RY = Reporting Year Value BY = Baseline Year Value