An updated version of the Water Balance Tool (WBT) developed by U.S. Pacific Northwest National Laboratory (PNNL) simplifies the estimation of a campus’s water balance. The online calculator captures a baseline of a facility’s current water use across major water end-uses, such as irrigation, cooling towers and vehicle wash.

The web-based software program automates the water balance process and is broadly applicable to many types of facilities. The tool is free and open to the public, requiring a Google account for access.

A survey user can develop a water balance using the online tool with data collected in a walk-through Source: Kelly Machart/PNNLprocess. Data inputs include water supply data, campus occupancy and information on all water end-uses present (plumbing, kitchen, laundry, vehicle wash, landscaping irrigation, cooling towers, steam boilers and other processes). The WBT then generates a report estimating water consumption by each end-use and compares the sum of all end-uses to the total water supplied to the campus. The resulting water balance data helps energy managers identify largest water consuming end-uses that represent good potential for water-saving opportunities and highlights system losses.

The WBT includes a detailed handbook with step-by-step instructions for conducting a walk-through water survey, including photos and general descriptions of typical water-consuming equipment.