TABLE 1.

Summary of Evaluation Design for the Four Water Conservation Strategies

Conservation Strategies and Evaluation Design	Sample Size	Date of Installation or Start of Implemention	Pre Period	Post Period or Simulation Period	Time Period Excluded From Analysis	Confounding Factors
Residential WSICS – Evaluation 1: Comparison of experimental group's outdoor water use prior to and after WSICS installation; weather controlled for by comparing to control group's outdoor water use during same time periods	Control: 71 Experiment: 9 (2 households in the Pilot Group for Evaluation 2 below were excluded from this analysis, as they joined the study in 2006-2007)	Summer of 2005	2001-2004 quarterly water use data from dedicated outdoor water meters	2006-2007 quarterly water use data from dedicated outdoor water meters	2005 water use data were excluded, because 2005 was a transitional year	Participation was voluntary. Self-selection may bias sample toward (1) high initial water users (expect positive savings) or (2) conservative initial water users (expect negative savings)
Residential WSICS – Evaluation 2: Comparison of experimental group's actual water use prior to WSICS installation to simulated water use with WSICS for same period, using known historic weather records	Experiment: 11	Summer of 2005 (9 participants) Summers of 2006 or 2007 (2 participants)	2003-2004 actual annual aggregated outdoor water use	2003-2004 simulated annual aggregated outdoor water use
Municipal WSICS – Comparison of actual water use prior to WSICS installation to simulated water use with WSICS for same period, using known historic weather records	5 ball fields	Summer of 2005	2003-2004 actual annual aggregated water use	2003-2004 simulated annual aggregated water use
Rainwater harvesting – Comparison of domestic (public) summer water use prior to and after installation of rainwater harvesting system; comparison of rainwater use and rainfall capture efficiency between 0.76 and 3.03 m3 systems	0.76 m3 (200-gallon) tank: 26 3.03 m3 (800-gallon) tank: 11 1.38 m3 (365-gallon) tank: 1 2.27 m3 (600-gallon) tank: 1	Mid-April 2006	2004-2005 domestic water use	2006-2007 domestic water use 2006-2007 rainwater use		Substantial difference in scale between domestic and rainwater use
Audit/retrofit and rebate programs – Comparison of winter water use prior to and after audit/retrofit event or installation of one or more rebate-qualifying appliance; participants grouped into mutually exclusive categories by type of participation. Control group used to control for external causes of pre v. post differences	Audit/Retrofit: 99 Rebate-toilet: 87 Rebate-washer: 527 Rebate-toilet and washer: 30 Audit/Retrofit and Rebate (toilet and/or washer): 32 Control group: 5,050	Variable, beginning September 2003 for Audit/Retrofits and July 2003 for Rebates	Quarterly winter water use from February 2001 to audit date or appliance installation date Control group established for each pre v. post period	Quarterly winter water use from audit date or appliance installation date to May 2007 Control group established for each pre v. post period	Only winter quarters included: (began on or after October 19 and ended on or before April 14)
Soil amendments – Comparison of simulated water use between control and experimental fields during same period, using known historical weather records and known weather triggers for irrigation on both fields	Control: 1 Experiment: 1		2003-2007 simulated water use data for control field	2003-2007 simulated water use data for experimental field