Chapter 11 -- National Handbook of Recommended Methods for Water Data Acquisition

Commercial activities also take place in institutions, such as hospitals, prisons, and schools; and in resorts; hotels; motels; camp grounds; and restaurants, therefore, commercial uses of water also includes food preparation, pools, and laundries. Water used for snow making at ski resorts and in water parks are potentially large commercial uses. Offstream fish hatcheries primarily engaged in hatching fish for release to public lakes and streams for fishing also are classified as commercial use. The Standard Industrial Classification (SIC) codes included in this category are identified in table 3 along with the primary uses of water in each SIC code group. Water use on military bases generally can be subdivided into domestic and commercial uses.

Water-use activities in the commercial category include withdrawals from ground or surface water; deliveries from water suppliers; consumptive use in the form of evaporation, usually during outdoor use, but also from washwater and food preparation; release into wastewater-collection systems; and return flow.

11.E.2. Sources of commercial water-use information

Many states have developed regulatory permit programs or reporting requirements or both for commercial users withdrawing greater than a specified threshold. Commercial water-use information often can be obtained from the State regulatory agency in States where permits or registration are required.The Safe Drinking Water Act encompasses all sources of public drinking water, even transient use in self-supplied restaurants, motels, and other commercial buildings. See the public water-supply section for a more complete discussion. Many commercial establishments are listed in business directories. Dunn and Bradstreet Information Services maintain an information base of almost ten million industrial, commercial, mining, and other business locations in the United States, including Puerto Rico and the Virgin Islands. The information base contains geographical, sales, employee population, product, and contact information.

State Departments of Employment or Economic Development are possible sources of data on commercial users in their State. These data may include (1) descriptions of major commercial users in each community, and (or) total number of employees by SIC code for each community or county. Frequently, these data are based on data compiled by the U.S. Bureau of the Census, but may be significantly enhanced in some states.

There are many professional associations, such as for ski resorts, fish hatcheries, that maintain a list of members or possibly list of all such facilities in their area. These lists may be free or may require purchase.

The U.S. Bureau of the Census is required by law (Title 13 of the United States Code--section 131, 191, and 224) to take an economic census every 5 years, covering years ending in 2 and 7. These economic census consist of the Census of Retail Trade, Wholesale Trade, Service Industries, Transportation, Manufactures, Mineral Industries, and Construction Industries. The results of each of the economic census are available in printed reports, for sale by the U.S. Government Printing Office, and on microfiche, computer tape, compact discs with read-only memory, and flexible diskettes, for sale by the U.S. Bureau of the Census. The Census of Retail Trade, Wholesale Trade, and Service Industries contain such statistics as number of establishments, employment, payroll, operating expenses, and capital expenditures for each State and its important metropolitan areas, counties, and places, by SIC groups and individual users.

Commercial water-use data (deliveries, releases) are available from customer records maintained by public water suppliers and wastewater-treatment facilities. The records' section for public water supply and wastewater-treatment facilities also may know of commercial facilities in their area that have large self-supplied water withdrawals. Care must be taken to ensure that only commercial users are included, not medium domestic users (apartment buildings) or small industries, and to take into account that large commercial users may be included in the industrial groupings by public water suppliers because of the large meter size.

Chambers of Commerce are a possible source of names and addresses of local commercial users, especially users that are likely to attract tourists, such as zoos, ski areas, water parks, hotels, motels, and major restaurants.

Figure 5. Diagram of commercial water use.

11.E.3. Measurement, estimation, and data-collection methods for commercial water use

Information on withdrawals from ground or surface water and major return flow may be available from State allocation and National Pollutant Discharge Elimination System (NPDES) permitting agencies. Data on deliveries from water suppliers and releases into wastewater-collection systems, as well as identification of major commercial users, may be available from the utilities. Consumptive use in the form of evaporation, usually during outdoor use but also from washwater and food preparation, are estimated from withdrawal, delivery, release, and return flow data or from information supplied by the commercial facility.

11.E.3.a. Primary data acquisition

Some commercial users always have high water use (fish hatcheries and facilities making snow for skiing) and will require a complete inventory of all types of these users. If there is no State program that regulates withdrawals for fish hatcheries, snow making, or amusement parks, it may be necessary to make onsite measurements. Other potentially large users, such as airports, hotels and resorts, shopping malls, hospitals, laundries, office buildings, and business parks, are more likely to meter their withdrawals or public water-supply deliveries. Consumptive use may be determined by installing flow meters at key points in the wastewater-collection system to monitor commercial wastewater releases and comparing the results with the withdrawals and deliveries.

11.E.3.b. Secondary data acquisition

Reported commercial water-use data may be available from a State allocation program, the USEPA FRDS data base on non-community suppliers, the PCS data base for commercial establishments with discharges to surface water, public water suppliers, and wastewater-treatment facilities. Surveys for water-use data can be made of commercial establishments identified through Chambers of Commerce and other community summaries, commercial information bases, or professional association lists. Estimates of withdrawal and public water-supply delivery data, by county and hydrologic unit, are available from USGS District offices

11.E.3.c. Derived data

Population estimates from the U.S. Bureau of the Census or other sources can be correlated with commercial water use for many types of commercial activities. However, the reliability of using coefficients to estimate commercial water use depends on the type of commercial activities. Coefficients are not accurate enough for estimating fish hatchery or snow-making use because each facility may be configured differently. Measurement of water withdrawal may not be necessary at every facility if information on how the facility is configured can be correlated with the specific configuration at other similar facilities.

Employee-based coefficients (where the number of employees in a single SIC code are multiplied by coefficient to estimate water use) are useful for estimating commercial water use if the coefficients are related to specific water-use activities. The SIC codes for commercial establishments and their associated water-use activities are listed in table 3. There are many factors that alter the suitability of applying these coefficients to specific SIC codes. Per employee water-use rates in some of the SIC code groups do not vary greatly, especially where sanitation is the primary water-use activity, such as in the majority of office buildings in which trade (50-59) and finance, insurance, and real estate (60-67) are conducted. However, large commercial complexes with fountains, lawn watering, and food preparation activities will have a higher rate of water use than would be estimated by the SIC code and employee-coefficient. Commercial water use within SIC code that include services (70-89) can vary depending on whether the commercial user has a restaurant, swimming pool, sauna, water-dependent air conditioning, or fountains. Seasonal variations in temperature and humidity outside the building will affect the rate of water use. Commercial water use also is affected by the presence or absence of water-use restrictions. All these factors tend to complicate the use of correlation coefficients using SIC Code and number of employees to estimate commercial water use.

Table 3. Commercial Standard Industrial Classification Codes.



SIC codes can be misleading in terms of how the water is actually used. For example, a corporate headquarters for a large manufacturer may have the same SIC code as the factory. A corporate headquarters may use water for air conditioning, fountains, sanitation, and lawn watering, all of which are commercial uses. Therefore, it important to examine the SIC code assignment closely to ensure the water use is categorized properly.

11.E.3.d. Quality assurance

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Quality assurance of commercial water use involves (1) comparing reported water-use data from withdrawal permit/registration programs, public water suppliers, wastewater-treatment facilities, and NPDES permits; (2) comparing commercial employee population from a manufacturers' directory with those included in U.S. Bureau of the Census publications; (3) checking account names in meter readings of public water suppliers to ensure that only commercial users are included; and (4) ensuring that corporate headquarters for industries are placed in commercial use.

Bowen, R.L., Leung, PingSun, and Vesenka, M.H., 1984, Water-use coefficients and resource multipliers for Oahu, Hawaii: Honolulu, University of Hawaii and Manoa, Water Resources Research Center Technical Report no. 164, 36 p.

Dziegielewski, Benedykt, Rodrigo, D.M., Opitz, E.M., 1990, Commercial and industrial water use in Southern California (final report): Los Angeles, Planning and Management Consultants, Ltd., report for the Metropolitan Water District of Southern California, 56 p. and 5 appendixes.

Kim, J.R., McCuen, R.H., 1979, Factors for predicting commercial water use: Water Resources Bulletin, v. 15, no. 4, p. 1073-1080.

Lynne, G.D., Luppold, W.G., and Kiker, Clyde, 1978, Water demand by retail and service business establishments--Dade and Monroe Counties, Florida: Gainesville, University of Florida, Agricultural Experiment Station Technical Bulletin.

McCuen, R.H., Sutherland, R.C., and Kim, J.R., 1975, Forecasting urban water use--commercial establishments: American Water Works Association Journal, v. 67, no. 5, p. 239-244.