Water Data Collection in the 2007 CBECS

CBECS 2007 - Release date: August 28, 2012

The 2007 round of the Commercial Buildings Energy Consumption Survey (CBECS) was the first time in the 30 year CBECS history that questions about water consumption were asked of respondents. EIA, in cooperation with the Environmental Protection Agency (EPA), added these questions to the CBECS because water and energy consumption are connected in many ways. Extracting, purifying, pumping and transporting drinking water, heating and processing water for domestic and other uses, and treating and disposing of wastewater are all activities that use energy. The California Energy Commission estimates that water has significant embedded energy content, between 2,000 and 20,000 kilowatt-hours per million gallons.¹ Currently there are no nationwide estimates of water consumption in the commercial buildings sector, and the CBECS was believed to be an appropriate way to collect this data. The questions about water in the 2007 CBECS were experimental. This report discusses the ability of respondents to answer the questions.

Water Data Collection in the 2007 CBECS

At the end of the 2007 CBECS questionnaire, respondents were asked to report the total volume of water used (consumption) in 2007, how much it cost (expenditures), whether the volume was metered or estimated, and how much of the water was used outside the building. If the building used central chillers, respondents were asked the volume of water used for cooling towers.

Four questions related to water consumption were also added to a section of the questionnaire regarding miscellaneous equipment: whether the sewer flow was metered, the presence of sterilizers or autoclaves, whether the building had a landscape irrigation system, and the number of commercial ice makers.

Prior to the CBECS interview, respondents were provided with advanced materials to prepare for the interview. A worksheet with these water questions was included so the respondent could gather the information, if available.

View the full text of the water questions and the worksheet.

Ability of Respondents to Report Water Data

Water Consumption and Expenditures

Overall, EIA considers this pilot water data collection a success. Among the 2007 CBECS sampled building respondents that used water, 56 percent of them were able to report consumption, expenditures, or both. Table 1 shows further detail on the ability of the overall 2007 CBECS sample respondents to report these data.

Water consumption and/or expenditures reporting rates varied substantially by principal building activity, as shown in Table 2. Inpatient healthcare buildings had the highest reporting rate of, at 69.4 percent. Public order and safety, education, lodging, public assembly, food sales, and religious worship buildings also had high reporting rates, above 60 percent. Vacant commercial buildings had the lowest rate, 35.8 percent.

Water consumption and/or expenditure reporting ability did not vary significantly across Census regions. All regions reported in the 50 to 60 percent range, as shown in Table 3.

Table 1 - Ability of 2007 CBECS Sampled Building Respondents to Report Water Consumption and/or Expenditures

	Number of Sampled Buildings	Percent of Sampled Buildings	Percent of Sampled Buildings that Use Water
Total	4,428	100	100
Water Not Used	358	8.1	—
Total Reported Consumption and/or Expenditures	2,289	51.7	56.2
Reported Both Consumption and Expenditures	1,453	32.8	35.7
Reported Consumption OR Expenditures	836	18.9	20.5
Did not know Consumption and Expenditures	1,781	40.2	43.8

Table 2 - Ability of 2007 CBECS Sampled Building Respondents to Report Water Consumption and/or Expenditures Data by Principal Building Activity

			Reported Water Consumption and or Expenditures		Did not know Consumption and Expenditures
	Number of Sampled Buildings	Number of Sampled Buildings that Use Water	Number of Sampled Buildings	Percent of Sampled Buildings that Use Water	Number of Sampled Buildings	Percent of Sampled Buildings that Use Water
All Buildings	4,428	4,070	2,289	56.2	1,781	43.8
Inpatient Health Care	173	173	120	69.4	53	30.6
Public Order & Safety	44	43	27	62.8	16	37.2
Education	299	292	179	61.3	113	38.7
Lodging	145	144	88	61.1	56	38.9
Public Assembly	170	164	100	61.0	64	39.0
Food Sales	81	79	48	60.8	31	39.2
Religious Worship	175	172	104	60.5	68	39.5
Office	1,074	1,052	626	59.5	426	40.5
Enclosed Mall	86	85	50	58.8	35	41.2
Outpatient Health Care	131	129	75	58.1	54	41.9
Other	235	216	124	57.4	92	42.6
Service	366	324	171	52.8	153	47.2
Warehouse	696	545	274	50.3	271	49.7
Retail Other than Mall	358	346	168	48.6	178	51.4
Food Service	242	239	111	46.4	128	53.6
Vacant	153	67	24	35.8	43	64.2

Table 3 - Ability of 2007 CBECS Sampled Building Respondents to Report Water Consumption and/or Expenditures Data by Census Region

			Reported Water Consumption and or Expenditures		Did not know Consumption and Expenditures
	Number of Sampled Buildings	Number of Sampled Buildings that Use Water	Number of Sampled Buildings	Percent of Sampled Buildings that Use Water	Number of Sampled Buildings	Percent of Sampled Buildings that Use Water
All Buildings	4,428	4,070	2,289	56.2	1,781	43.8
Northeast	847	787	410	52.1	377	47.9
Midwest	1,102	962	572	59.5	390	40.5
South	1,793	1,669	972	58.2	697	41.8
West	686	652	335	51.4	317	48.6

Miscellaneous Water Questions

• Sewer flow metering
  About 91 percent of respondents were able to answer whether or not their sewer flow was metered.

• Sterilizers or autoclaves
  Over 99 percent of respondents were able to report whether or not there were sterilizers or autoclaves used in the building.

• Landscape irrigation system
  Over 99 percent of respondents were able to report whether or not the building had a landscape irrigation system.

• Commercial ice makers
  All buildings that used electricity (4,259 buildings) were asked whether there was refrigeration equipment present in the building. Some type of refrigeration equipment was in 81 percent of these buildings. Respondents that reported the presence of commercial refrigeration were shown a list of seven types of refrigeration and were asked which types were found in the building. In the 2007 CBECS, one of these seven types was new to the list – commercial ice makers. Of the respondents asked about refrigeration types, 98 percent of them were able to answer whether or not they had ice makers, and 94 percent of those that had ice makers were able to report the exact number.

• Water metered/estimated
  All buildings that reported a water consumption figure were asked how the figure was determined: metered, estimated, both metered and estimated, or measured in some other way; 97 percent of the respondents were able to report how the figure was determined.

• Outside water consumption
  All buildings that reported a water consumption figure were asked how much of the total water was used outside the building. About 81 percent of the respondents were able to report the outside water consumption figure.

• Cooling tower water consumption
  Buildings that reported a water consumption figure and had a central chiller inside the building were asked how much of the total consumption was used for the cooling tower; 50 percent of these respondents were able to report their cooling tower consumption.

Conclusion

The collection of water consumption data in commercial buildings was experimental in the 2007 CBECS. Prior to conducting the survey, it was unknown whether many CBECS respondents would be able to report this information. Of the responding sampled buildings, 56 percent of all responding sampled buildings were able to report consumption or expenditures or both. Reporting success varied by building type, with inpatient healthcare buildings reporting at the highest rate, 69 percent.

As a result of the success of the data collection in the 2007 CBECS and the strong relationship between water and energy consumption, EIA plans to collect water data again in the 2012 CBECS, with improvements based on lessons learned from 2007. Data collection for CBECS 2012 will begin in early 2013 and EIA plans to publish the water estimates for the entire commercial buildings population in 2014.