Module 4: Water Efficiency

Collecting Data in Institutional / Commercial Buildings

A water audit will identify the quantities, characteristics, and uses of all water on the site. Included in a water audit:

Inventory of water use areas
Measure of actual use where practical (bucket & stopwatch or meters)
Locate leaks
Identify facility practices
Quantify water quality needs (potable vs. Reuse)

Measurements can be as simple as using a bucket and stopwatch and counting drips from leaks. P²AD has several spreadsheets that can be used to help gather and evaluate the data collected in this process, and links to them are included in the Resources section of this module.

Meters provide information that, when tracked and evaluated, allows staff to make educated choices about how to properly operate energy- and water-consuming equipment and systems (for example, cooling towers, boilers and irrigation). These choices will eventually influence water consumption, costs, and overall building performance. Although reasons for metering may differ from site to site, some common ones are listed below:

To monitor and verify existing utility usage
To evaluate utility rate plans
To measure, verify, and optimize equipment performance
To allow direct billing of the actual—not estimated—consumption of each tenant’s utilities
To manage water consumption
To allow leak detection

Types of meters

Several types of meters are commercially available. For water and other flow-related applications, meters are typically an in-line installation using positive displacement, insertion turbine, or pressure-related techniques. Depending on the need, any of these meters will vary in size, type, output configuration, accuracy, and price. Make sure the meter can be located where it will be read. Meters that require ladders, steps, or are located in awkward areas are not likely to be read properly or consistently. Look at utility bills monthly and compare with recorded meter flows and historical data.