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Ordering Information:
ORDER NUMBER: 90806
DATE AVAILABLE: Summer 2000
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Printed Report |
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PRINCIPAL INVESTIGATORS:
William DeOreo, Peter Mayer, Benedykt Dziegielewski, Jack C. Kiefer, Eva M.
Opitz, Gregory A. Porter, Glen L. Lantz, and John Olaf Nelson
OBJECTIVES:
The purpose of this study was to summarize and interpret the existing knowledge
base on commercial and institutional (CI) uses of utility-supplied potable water
in urban areas; present the results of field studies in a sample of 25 establishments
in 5 urban areas; provide econometric end-use models for various categories
of CI customers; and develop a set of efficiency benchmarks for five selected
CI categories-restaurants, hotels and motels, supermarkets, office buildings,
and schools.
BACKGROUND:
The water use of CI customers involves approximately one-fourth of
the total quantity of water demanded for an urban area. Despite the substantive
proportion of total urban water use for CI customers, very little attention
has been focused on the water usage of this sector. Possible reasons for the
lack of attention may relate to the heterogeneous nature of the CI sector and
a lack of knowledge regarding the quantities of water used for specific purposes.
The CI sector consists of a large number of dissimilar customers with regard
to the purposes of water use. The lack of benchmark measurements for the quantities
of water used for cooling, cleaning, sanitary, and landscape uses within subgroups
of similar establishments is an obstacle to designing CI water efficiency programs
and to developing reliable estimates of CI water use and efficiency savings.
HIGHLIGHTS:
The information on the opportunities for water conservation described
in this study can be summarized in terms of the following findings and implications
for the design and implementation of CI conservation programs:
- Some large-water-using categories have been ignored for water audits.
- Potential savings are in the 15- to 50-percent range, with 15 to 35 percent
being typical.
- Many CI water users do not need to use potable water in all applications.
- Discussion of the successes and failures of other programs can provide insight.
APPROACH:
As part of this study, an analysis of CI categories and water use was
performed on billing data from five participating water providers. A complete
set of billing records for a period of one year was analyzed including
- analysis of CI categories and use in each city independently
- comparison of CI categories and use across the five sites
- development of data that can be used to rank the categories according to
conservation potential
Five categories were selected for detailed analysis: schools, hotels/motels,
office buildings, restaurants, and food stores.
The statistical analysis of establishment level data for the five selected
categories of CI urban water users permitted estimation of models for predicting
total water use in establishments as a function of size, magnitude of operation,
specific type of establishment within a broad category, and presence of specific
end uses. Data for a total of 433 establishments among the five CI categories
were used to develop the statistical models. These data were derived from available
water use audit databases.
RESULTS/FINDINGS:
The audit databases and data collected from field studies of 25 CI
establishments
(5 from each selected category) were analyzed to determine the benchmarks of
average and efficient rates of water use for each category of establishment.
The comparison of results from three sources (i.e., audit data, field study
data, and modeled audit data) allowed the derivation of expected average rates
of water use for various purposes as well as approximate values of efficient
use.
Restaurants
The data suggest that an efficient restaurant would use approximately 130 to
331 gallons of water per square foot of building area in a year.
Hotels and Motels
The data suggest that an efficient hotel or motel would use about 60 to 115
gallons per day per occupied room for indoor purposes.
Office Buildings
The data suggest an efficient office building's total water use should range
from
26 to 35 gallons per square foot per year.
Supermarkets
The data suggest that an efficient supermarket would use between 24 and
52 gallons per square foot of building area in a year.
Schools
The data suggest that an efficient school would use about 8 to 16 gallons per
square foot per year for indoor use.
IMPACT:
The results of this study and the insights gained through the field
investigations and data modeling and analysis support the following recommendations
for the management of water demands in the CI sector of urban water users.
- A standardized classification scheme of CI customers should be developed
by the water industry to facilitate both demand planning and evaluation of
conservation programs.
- Meaningful aggregate benchmarks can be developed by collecting additional
aggregate data on the size of the CI activity represented by a category.
- Utilities should consider developing efficiency benchmarks for their larger
CI end users.
PARTICIPATING UTILITIES:
- Seven utilities in California and Arizona participated in this research.