This is a performance-based prerequisite that must be documented through the Arc platform. Teams enter water consumption into Arc using data from utility bills or invoices. The data must account for all potable water used by the project—irrigation, indoor plumbing fixtures, domestic hot water, process water, reclaimed water, boiler water, and cooling towers. Additionally, the data must cover at least 12 consecutive months with no gaps or missing data.
Meters are a must
Your project must have permanently installed metering that captures total potable or reclaimed water use. It’s wise to confirm that meters are installed and functioning properly to ensure that the data you receive is accurate.
Interiors projects have two options. Projects with permanently installed sub-metering that captures potable water use within the project scope are all set. Alternatively, projects can pro-rate water use based on occupancy and base building water use.
A link to Energy Star
Teams have the option to share water data from Energy Star Portfolio Manager. See the Documentation Toolkit for guidance on how to setup water data sharing between Portfolio Manager and Arc.
A prerequisite with points
A minimum performance score of 40 must be achieved to earn this prerequisite. Your project will receive 6 LEED points for reaching this threshold. Additional points (up to 15) are achieved as your performance score increases.
Performance scoring
This prerequisite assesses the total potable water used by a project. This includes both water used in the building and water used to irrigate any landscaping. The Arc platform uses a few key building details to generate a water performance score, including total potable water consumption, gross floor area, weighted occupancy, and weighted operating hours. The Arc platform also compares your water use against other high performing buildings worldwide (ie—other LEED certified projects). Check out the LEED v4.1 O+M Beta Guide for more details on how water performance is scored in v4.1.
What’s New in LEED v4.1
- This is a new prerequisite that assesses metered water consumption
- Both indoor and outdoor water use are assessed together with a single performance score
- No more USGBC Excel calculators—everything is calculated by the Arc platform
- Performance is based on actual water usage data as provided on utility bills or invoices
Should I upgrade?
The only way to determine your v4.1 water performance score is to enter 12 months of total potable water use data into Arc, which makes the decision to upgrade a tricky one. Sites with large landscaped areas that require large amounts of irrigation water may score poorly on Arc. When choosing between rating systems, be sure to take the points allocations into account. You can earn up to 15 points under v4.1, compared to 12 points for all credits in the v4 Water Efficiency category.