Evaluation of Water Harvesting Rebate Programs in Tucson, AZ

Abstract

As water becomes scarcer, many water providers are looking for ways to encourage conservation. Water reuse is a critical part of water management, and because there is a set amount of water, deciding how and when water is reused will be a continuing and necessary debate. A 2016 National Academy of Sciences report on graywater, a hotly argued form of reuse, identifies several areas on needed research including assessing regulatory innovations to increase onsite water use, understanding how water harvesting systems affect water use behavior, assessing user knowledge of water harvesting systems, and further understanding the extent that best management practices are practiced. This research provides insight into some of these needed research areas. In Arizona, Tucson Water has used various measures to encourage conservation such as rebates or tax breaks for low flow toilets and fixtures, high efficiency washing machines, graywater systems, and rainwater harvesting systems. This research, focused on Tucson Water's rebate programs for installing water harvesting systems, takes a closer look at the maintenance requirements of water harvesting systems and the effect that water harvesting systems have on property vegetation. This thesis is composed of two parts: a survey of rebate recipients focused on maintenance and remote sensing of properties of rebate recipients to analyze changes in vegetation (greenness). The survey was completed with a 43% response rate, and remote sensing reveals no significant vegetation difference between properties that harvested water to those that did not. This thesis will present the findings of this study, which will elucidate unstudied aspects of water harvesting. Understanding some of the ramifications of residential level water harvesting, such as the programs encouraged by Tucson Water, will be an important part of informed decisions.