To meet this prerequisite, teams must design and install plumbing systems using high efficiency indoor plumbing fixtures including lavatory faucets, toilets, urinals, kitchen sinks, and showerheads, and determine how much potable water is consumed relative to a LEED baseline case.

In order to meet the prerequisite, a minimum of 20% savings must be demonstrated.

The calculation is performed using a calculator developed by USGBC. Teams should become very familiar with the calculator, the information needed to complete it, and the various rules for using it in order to accurately assess performance and demonstrate prerequisite compliance.

In addition to meeting the 20% performance threshold, teams must select WaterSense labeled fixtures for any fixture type that is eligible for the WaterSense label. Remember that your project must also meet prescriptive requirements for appliances and process water equipment, including clothes washers, dishwashers, pre-rinse spray valves, ice machines, heat rejection and cooling, cooling towers, and evaporative condensers. 

What’s New in LEED v4

• This prerequisite now has criteria for water-using appliances and processes, cooling towers, and evaporative condensers.
• WaterSense label requirements are now mandatory in the U.S., with local equivalents accepted for projects outside the U.S.
• USGBC added a new prescriptive compliance path option that requires all fixture rates to be 20% below the specified baseline rates.
• Duration-based savings from autocontrol faucets with sensors or metering controls are no longer allowed, since studies have shown that autocontrol faucets do not produce water savings.
• Teams can no longer apply nonpotable water in the prerequisite calculation.