By: Aubry Wolff, Diane E. Boellstorff and T. Allen Berthold
Conservation programs work best when they are targeted to the biggest water users. To save the most water at the lowest operational cost, each utility needs to evaluate its customers’ water use before determining appropriate conservation programs.
One process for characterizing customers is to gather, prepare, and analyze existing data. The process varies among utilities, depending on available information, time, and expertise. If data and time are lacking, a utility could begin with single-family residential accounts, leaving nonresidential accounts for later examination.
Phase I: Gather data
To illustrate this process, we analyzed data from 17,774 residential accounts from 2009 to 2013. Table 1 shows the water use (in gallons) by customer category as assigned by the utility.
The data included:
- Billed consumption by account (available from the utility)
- Individual property information (available from a local appraisal district)
Other data could include demographics from the US Census Bureau and spatial information from the city or appraisal district.
Phase II: Prepare the data
To prepare the data for analysis, we removed nonessential accounts, separated the accounts by customer category, and integrated property data into the consumption information. This data preparation made it easier in the next phase to identify account characteristics across a wide range of consumption levels.
The next steps were to determine seasonal (monthly outdoor) use and winter (indoor average) use by calculating each account’s winter average.
Phase III: Analyze the data
First, identify the characteristics of high-consumption accounts. Compare annual consumption with aggregate consumption by ranges of property build-dates and assessed home values. These distributions help identify the characteristics of high-consumption accounts.
Assign both seasonal (monthly outdoor) and winter-use (indoor average) levels to each account to characterize their consumption. Then make a cross-comparison to further categorize customer accounts by similar consumption trends. Determine the annual and aggregate number of accounts, and from that information, calculate the annual and aggregate change in the number of accounts.
Assign a use level to each customer account based on percentiles of seasonal and winter monthly averages. Compile the customer-use levels into one data set of annual consumption. This data set will help you divide the customers into groups of similar consumption trends and determine where to target conservation programming. Table 2 shows the final, prepared data set for the 17,774 open, residential accounts used in our analysis example.
To see how consumption changed over time, calculate the 5-year change in the number of accounts within each category (Table 3). The goal is to increase the number of lower- consumption accounts and decrease the number of higher- consumption accounts.
Then determine which groups used the most water during the 5-year period (Table 4). These groups offer the greatest opportunity to achieve water savings.
The average annual consumption per account (Table 5) is based on aggregate consumption data for all 5 years. The blue baseline (estimated indoor need) shows those accounts whose annual consumption indicates efficient consumption—they are using only what they need.
Adopting this or a similar customer characterization process makes it easier and faster to target conservation efforts to the accounts using the most water.
Anna Faloon, Ph.D. student in the Department of Civil Engineering at Texas A&M University, developed the method used in this publication for categorizing water usage.
For more information, download ESC-044 Residential Customer Characterization Guide for Urban Water Conservation Planning, Texas A&M AgriLife Extension Service, http://www.agrilifebookstore.org, or contact Diane Boellstorff at email@example.com.
Download a printer-friendly version of this publication: Evaluating Customer Water Use to Create Effective Conservation Programs
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