Appropriate design and evaluation of water use and conservation metrics and benchmarks

Abstract

This article provides water utility managers with guidance on alternative measures of water use and how these measures, or metrics, can be most appropriately used for comparing and evaluating water efficiency. There is currently no universally perfect metric for describing water use, but several metrics are better than per capita use in terms of the available data's accuracy and informational value. Water utilities and regulators have an increasing need for meaningful performance indicators and benchmarks for measuring and comparing water use. Significant improvements in the ability of water utilities to reduce “definitional noise” in monitoring and comparing water usage rates would be achieved if the water supply industry adopted a standard set of customer types and customer classification procedures. Available water production and sales records can be used to calculate both systemwide and sector‐specific metrics of water use. For a systemwide metric, the only accurate and regularly updated measure of system size is the number of connections or customer accounts.

Benchmarking Water Use in the UK Food and Drink Sector: Case Study of Three Water-Intensive Dairy Products

“…Benchmarks are either absolute or relative or even unitless [21]. Absolute benchmarks come in the form of per capita water use/day which is exact, while relative benchmarks manifest in the form of water conservation or reduction strategies like 30% per capita water use reduction by 2014.…”

“…Unitless benchmarks such as ratios and percentages represent relative benchmarks and are often target values. According to Kunkel et al [41] cited in [21], an example of an absolute water benchmark is the Infrastructure Leakage Index (ILI) which is defined as the ratio of yearly water losses during transmission and distribution to an estimated value of unavoidable leakage.…”

Outdoor Water Use as an Adaptation Problem: Insights from North American Cities

“…Minimum month and seasonal use approaches compare use in the minimum month (which is assumed to be indoor) and use in the maximum month (Gage and Cooper 2015). The difference between the two is assumed to be outdoor use (Dziegielewski and Keifer 2010). This approach is limited by the fact that some outdoor water use occurs in the winter, particularly in warm-climate regions.…”

Evaluating the effectiveness of water restrictions: A case study from Southeast Florida

“…The mathematical definitions of T and U can be scaled according to the scope of the water conservation program. For example, the CER is suitable for monitoring progress toward target use in regional conservation initiatives, municipal water supply plans, and community lawn water restriction programs (Dziegielewski and Kiefer, 2010).…”