Audit Methodology

Chapter 5: Designing the Water Efficiency Program

5.1 Introduction

The water efficiency program should be designed to incorporate water reduction measures that best achieve the goals set out for the activities at the facility. Steps leading to such a program may include

1. establishment of the goals of the water reduction program
2. identification of all reasonable reduction measures
3. identification of positive and negative impacts of the reduction measures
4. preliminary evaluation to screen out undesirable measures
5. a cost-benefit analysis
6. development and evaluation of the recommended water reduction program

5.2 Goals

A government facility may implement the water efficiency program to achieve several goals. Some examples are listed below:

• participation of the water users
• water and/or cost savings
• long-term solution
• improved public image

The management of the facility will likely play a major role in establishing goals for the program.

5.3 Alternative reduction measures

For each water use category, water reduction measures and practices can be identified specific to the facility. When the list of available measures has been completed, then the intangible impacts, as well as financial and water savings impacts of each measure, must be evaluated against the goals set by water efficiency program of the facility.

5.4 Impacts of water reduction measures

The following impact categories need to be considered: economic, social/political, and environmental/technical. Specific impacts that should be determined for the measures include public (user) and political acceptance, environmental impacts, reliability, short- or long-term effectiveness, and other impacts specific to the goals of the program. The impact of water reduction measures on the goals of the facility needs to be determined.

5.5 Cost-benefit analysis

A cost-benefit calculation will determine the net savings that would be made by the most cost-effective water reduction measure. To obtain the information needed to derive the costs and savings, a detailed examination of the potential water reduction measure must be undertaken.

The general approach to calculating the net benefits of a reduction measure is shown below:

TANB ($/y) = AECS ($/y) - ACCO ($/y) - AAOC ($/y)

Where

• the total annual net benefit (TANB [$/y]) is the net economic benefit that would result if the measure were implemented
• the annual expected cost savings above existing operation (AECS [$/y]) includes savings in water supply and sewer charges, surcharges, and possibly energy
• the amortized capital cost of operation (ACCO [$/y]) includes the equipment, materials, and installation of the measure, amortized over the projected life of the measure
• the additional annual operating cost above existing operation (AAOC [$/y]) is the additional cost of labour, maintenance, energy, materials, and waste disposal that would result if the measure were implemented

In most cases, however, a simple cost-benefit analysis involving the estimated capital cost of the modification works, the net revenue savings, and the resulting payback period should suffice. Other non-quantifiable benefits, including those related to the environment, social well-being of water users, political image and goals, must always be considered although they cannot be included in the calculation of net benefits.

5.6 Development of recommended water efficiency program

The results of the impact assessment and cost-benefit analysis may be used to develop a water efficiency program to meet the goals of the facility. The resulting program will consist of a number of compatible water reduction measures and will have a net benefit and net water volume savings, as well as a number of non-quantifiable benefits.

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