LITERATURE REVIEW

Most analyses of low-consumption rebate programs show that low-consumption toilets save water compared to conventional fixtures. In Los Angeles and Santa Monica, a study of Metropolitan Water District of Southern California’s ultra low flush rebate program for single family residences and multifamily residences found water savings ranging from 30 to 46 gallons per dwelling per day, depending on the dwelling type (Chesnutt et al. 1992). In Tucson, an analysis of Tucson Water’s low-consumption rebate program showed that toilet retrofits saved an average of 33 gallons per dwelling per day, or 26 gallons per toilet per day. This study included only single family residences (Woodard and Henderson 1994).

Customer satisfaction surveys show that the majority of customers are satisfied with most brands of low-consumption toilet, when the toilets are relatively new. Homeowners participating in the low-consumption toilet rebate program in New York City were surveyed in 1996 after approximately 7 to15 months of toilet use, and had an average satisfaction rating of 3.16 on a 5- point scale, indicating they were slightly more satisfied with their new toilet compared to the old one. Apartment residents rated their low-consumption toilet on average at 2.94, indicating they were slightly less satisfied with their new toilets (Westat 1997).

In 1992, customers participating in the toilet rebate program offered by the Los Angeles Department of Water and Power were surveyed. How much time elapsed between toilet installation and the survey is unclear. The average satisfaction rating for all brands of toilets was 7.4 on a 10-point scale (Wirthlin Group 1992). This study had toilets of the same model and year as the current study, including the Kilgore/Mansfield Quantum, the Kohler Wellworth Lite, the Universal Rundle Atlas and the Eljer Preserver.

In 1999, Metropolitan Water District of Southern California surveyed customers who installed new low-consumption toilets in 1998 or 1999. Average ratings by model of toilet ranged from 5.91 to 8.37 on a 10-point scale. Most customers preferred the new low-consumption toilets to the old toilets (MWD 1999). Respondents to a 1996 MWD survey provided average ratings ranging from 3.6 to 4.46 on a 5-point scale.

Most customer satisfaction surveys are performed about a year after toilets are installed. There has been anecdotal evidence that functioning of some low-consumption toilets can deteriorate over time, starting as early as a few months after installation. However, no studies have been done of customer satisfaction with low-consumption toilets more than about a year into their expected 20-year life. And, no studies have been conducted that gathered data on the functioning of older low-consumption toilets by measuring the water flow rate at the water meter for the house in which the low-consumption toilet was installed.