Rainwater harvesting is increasingly being turned to as a viable water conservation measure in the face of increasing water shortages. Legislatures at local, state, and national levels have begun implementing legislation that regulates rainwater harvesting; in some cases, governments choose to make the practice mandatory. This article examines four mandatory rainwater harvesting policies implemented in Australia, India, and the United States. The article summarizes the relative success of each policy's adoption, and then moves on to discuss the impact of the policy on overall water conservation. In comparing the relative success of the policies, one finds that while financial investment plays an important role in determining the impact of the programs, other factors, such as the leniency of the mandate, cost to consumer, and support from non-governmental organizations play an important role in determining whether the policies are adopted. Furthermore, policymakers can encourage greater water conservation by incentivizing behavioral change and creating more robust financial incentives.
TABLE OF CONTENTS INTRODUCTION I. Rainwater Harvesting Techniques II. Case Studies A. Tucson 1. Adoption 2. Conservation B. Bangalore 1. Adoption 2. Conservation C. Queensland 1. Adoption 2. Conservation D. Tamil Nadu and Chennai 1. Adoption 2. Conservation III. Policy Analysis and Suggestions A. Socioeconomic and Cultural Impacts B. Adoption 1. Severe vs. Lenient Mandates 2. Minimize Cost to Consumer 3. Non-Governmental Support C. Conservation 1. Encouraging Behavioral Changes 2. Financial Incentives CONCLUSION INTRODUCTION
By 2025, two-thirds of the world's population may face water shortages. (1) Numerous factors contribute to this projection; global climate change, expansion of business activity and urbanization, and increased population are stressing the world's supply of freshwater. (2) Rainwater harvesting (RWH) is one means of mitigating this impending water scarcity. Research demonstrates that a single rain barrel can provide up to 25 to 30 percent of indoor, non-potable water demand for the average household in water-scarce cities. (3) Moreover, with extreme weather events like intense flooding and extended drought becoming increasingly common, RWH offers the benefits of catching excess rain during heavy downpours and storing it for use during prolonged drought. (4) Urban areas can benefit by trapping the vast amount of water that evaporates or runs off of impervious surfaces, like pavement or concrete, after a storm. (5) Rural areas can similarly reap the benefits of collecting water for later use by storing water in an above-ground tank or directing storm water to water-catchment areas.
The potential for increased conservation through RWH is beginning to be recognized. Worldwide, city and state governments have started to implement RWH policies to encourage water conservation. (6) Policymakers comment that RWH can be a "vital strategy in adaptation to climate change" and have taken steps to formalize, codify, and establish comprehensive RWH policies and programs. (7) These programs employ a variety of mechanisms to promote conservation through RWH, including statutory and regulatory codification, market-based incentive systems (e.g., rebates or subsidies), and combinations of the two. (8)
A comparative analysis of the successes and failures of existing RWH programs can help to increase the efficacy of the growing number of government-led RWH policies. (9) This article assumes that an RWH program should achieve two objectives. First, it must encourage adoption and use of RWH technologies; and second, it should result in decreased reliance on more traditional water sources, such as municipal water supplies, so as to positively impact overall water conservation. This article uses four case studies of policies in Tucson, Arizona; Bangalore, India; Queensland, Australia; and Tamil Nadu and Chennai, India to offer insight into how market-driven and codified RWH policies achieve these outcomes. I first outline how each of the geographic locales employed varying levels of mandated use and market-based incentives to encourage adoption of RWH, then move on to discuss how these programs have impacted overall conservation.
This article focuses on each policy's ability to drive RWH adoption and water conservation; however, it does not provide substantial analysis of the cultural and socioeconomic factors operating in the background of these policies. Thus, one should not consider it to be a wholly comprehensive analysis of the programs' operations in each of the areas. Moreover, this article does not discuss numerous other RWH programs that have been implemented around the world. (10) Although this article does not provide a complete picture of RWH, by identifying patterns in the successes and failures across the four locations discussed herein, it offers insights for policymakers intending to implement a RWH program and provides foundational knowledge to guide future research.
Part I of this article briefly discusses common methods for harvesting rainwater to provide necessary background knowledge. Part II offers four case studies: Tucson, Arizona, where the local municipal government implemented a hybrid system of market-based incentives and mandated RWH installation; Bangalore, India, where the local government mandated RWH installation for all buildings of a certain size; Queensland, Australia, where the state first mandated the installation of RWH tanks for new construction and provided incentives for installation of RWH tanks on existing structures; and Tamil Nadu, India, where the state mandated RWH structures on all buildings. Information is provided for each case study regarding the demographics of the location, its water governance structure, the RWH program, and the policy's ability to drive RWH adoption and overall water conservation. Part III goes on to discuss the successes and failures of the programs. Subpart III.B outlines considerations related to driving adoption of RWH technologies, suggesting that policymakers carefully consider the severity of any mandates to be implemented, minimize the cost of implementation to the consumer, and look to grassroots organizers to provide support in the community. Subpart III.C moves on to discuss how policymakers can ensure that RWH, once adopted, results in higher levels of water conserved. Barriers to conservation are then highlighted, such as attitudinal apathy toward RWH and a lack of strong financial incentives to conserve harvested water. The article concludes by providing suggestions for policymakers hoping to drive conservation.
RAINWATER HARVESTING TECHNIQUES
Numerous techniques are available to practice RWH. Two of the most common are passive (external) harvesting and active (domestic) harvesting. (11) In passive harvesting, rainwater runoff is directed to sub-surface, underground catchment areas, where the water seeps into the soil and recharges the groundwater supply. (12) Methods for passive collection include water harvesting infiltration areas, as well as systems that direct water from a rooftop or other location to areas where it can be stored for future use. (13) In active harvesting, rainwater is collected from surface areas and stored in above-ground rainwater tanks or cisterns. (14) Typically, active systems are more costly than passive systems. (15)
Passive RWH systems may be especially beneficial in low-income areas, as many low-income families still rely on municipal sources for their water and do not have the space or financial resources to install an active RWH system. As M. Dinesh Kumar of the International Water Management Institute notes, in low rainfall areas, often the only people who benefit from active RWH are the wealthy or those who have a large roof area and room for storage that can handle high volumes of rainfall. (16) Thus, by installing passive rainwater harvesting systems, even low-income households can contribute to greater underground recharge across the geographic area.
The desert city of Tucson is nestled in the southern portion of Arizona near the U.S./Mexico border. The income per capita is approximately $20,437. (17) As the city receives only twelve inches of rainfall each year, (18) Tucson Water (the municipal water authority that provides water to the majority of Tucson and the surrounding areas19) looks to a number of sources to obtain a municipal water supply for its 530,000 residents. (20) Sources include mined groundwater, aquifers in the area, and allocations from the Colorado River. (21) In this desert city, studies show that harvested rainwater usage could reduce residential water usage by 30 to 40 percent. (22)
In October 2008, Tucson became the first city in the United States to mandate RWH installation in commercial buildings when it amended the city's municipal code and development standards. (23) Passed unanimously by the city council, (24) the amendments mandated that 1) commercial development and site plans include an RWH plan, and 2) 50 percent of landscaping water demand be met using the harvested water collected through either active or passive harvesting. (25) At the same time the mandates were implemented, the city also created a rebate system for residential users. (26) Under the system, qualifying users became eligible for rebates of up to $2,000 for installing rainwater harvesting cisterns, and up to $500 for installing passive RWH systems. (27) Those applying for the rebate had to attend a mandatory workshop that focused on passive and active rainwater catchment systems for residential ownership. (28) Tucson funded the rebate program, as well as other conservation programs, by charging municipal users a $0.25 fee on their monthly water bills. (29)
Local grassroots activists played an integral role in passing the amendments. A group of local stakeholders...