Module 4: Water Efficiency

• Overview
• Program Planning
• Collecting Data
• Common Options
• Running your program
• Resources

Overview

Water-efficiency programs can result in savings in the cost of water, sewer, and energy. This module provides an overview of water efficiency in institutional and commercial buildings with the intention of evaluating types of water uses, current water-efficient technologies available, and potential water-conservation savings that could be achieved.

Regulatory Guidance

The Energy Policy Act of 1992 (EPAct 1992) establishes minimum energy- and water-efficiency levels for classes of covered products as shown in Table 1. The US Green Building Council’s Leadership in Energy and Environmental Design (LEED) rating system uses these EPAct standards to establish water-use baselines. Points are earned for reducing water use beyond the baseline results. LEED ratings are described further in Module 6: Sustainable Building.

* gpf = Gallons per Flush, ** gpm = Gallons per Minute *** psi = Pounds per Square Inch

Primary Water Uses in Institutional and Commercial Buildings

Institutional and commercial uses of water mainly encompass domestic uses (toilet flushing, hand washing), heating and cooling, and landscape irrigation. Domestic water use usually represents the highest water use at 35–50 percent (Vickers 2001).

Irrigation

As can be seen in the following chart, irrigation can account for 38 percent of a building’s water use.

Domestic Water Use

Water use that is not associated with the main company activity is regarded as domestic water use. For example, water required for laundry washing in a commercial laundromat is not considered domestic as it is their primary business activity, while laundry washing at a hospital would be considered domestic use as it is ancillary to their primary business activity. Domestic water use includes water used for toilet flushing, hand washing, and general cleaning.