Harvesting a New Standard
Bob Ferguson

In past columns, as well as related articles in publications such as Water Quality Products (a sister publication to Water & Wastes Digest), I have written about the growing field of rainwater harvesting. The regulatory environment across the country has been changing in recent years to encourage the collection and storage of rainwater to enhance freshwater supplies. Rainwater can be used for a number of non-potable applications—irrigation, laundry, toilet flushing, etc.—and it reduces the demand for water from distribution systems that is treated to drinking water standards. States and municipalities across the country have been enacting legislation requiring, or at least highly incentivizing, the use of rainwater in commercial buildings and new construction.    

Hasty Harvesting

There are, however, people in the industry who are concerned that the attractiveness and promotion of rainwater harvesting is such that the technology and its development will move too fast and potentially get ahead of itself. I have cited the solar energy industry’s problem: higher expectations than what it economically or technically has been able to deliver on. I also have written about a controversy in New Orleans where proponents of rainwater collection went head to head with local public health officials. The rainwater harvesting proponents cited its advantages in reducing the demand and expense of using water treated to potable standards for non-potable applications, and also as an alternate water supply during times of extreme need (such as the aftermath of Hurricane Katrina). Public health officials, on the other hand, were concerned about unintended health impacts such as chemical exposures (e.g., from paints, coatings or other construction materials that could leach chemicals into the water from inappropriate cisterns) or mosquitoes. The water table in New Orleans is high, and tanks stored belowground need to be kept full to serve as ballast to keep them from floating to the surface—but full water tanks in Louisiana are a breeding ground for mosquitoes.  

These issues were not specifically addressed by local codes or standards, and their potential impact concerned public health officials. People in the rainwater harvesting industry should be, too. An unintended contamination or public health incident could tarnish the reputation and potential of rainwater harvesting for decades. Ensuring that the development of the technology moves forward in step with the development of regulations and standards can help to prevent such a problem.

A National Standard

Late last year, the American Society of Plumbing Engineers (ASPE) took such a step and announced that ARCSA/ASPE/ANSI 63-2013: Rainwater Catchment Systems had been approved as an American National Standard by the American National Standards Institute (ANSI). The standard was jointly developed by ASPE and the American Rainwater Catchment Systems Assn. (ARCSA) and co-sponsored by the International Association of Plumbing and Mechanical Officials (IAPMO) and NSF Intl. The standard was designed to help avoid problems similar those I mentioned by providing a consensus national standard by which users, designers, installers and regulators of rainwater systems can safely implement rainwater catchment and storage systems. The standard addresses key issues such as acceptable materials for catchment, distribution and storage components; sizing and design requirements; installation specifications; minimum requirements for storage tanks and devices; backflow prevention; and requirements for systems that are connected or adjacent to public potable water systems, as well as standards for treatment and disinfection of
captured rainwater. 

The standard originally was published in 2007, but in order to earn the American National Standard designation, an expert working group under the ASPE Plumbing Engineering Design Standards Committee led an extensive revision process. Following the ANSI standards process, these experts solicited input from the public and interested parties and incorporated comments and input from stakeholders in many fields, including construction, irrigation, water treatment, and public health and regulatory agencies. 

Having administered a number of national standards and directed certification programs, I recognize their value in helping the development of new technologies. Putting national standards in place helps to provide guidelines and a framework on which state and local regulators can base their codes and thereby prevent a patchwork of multiple standards, codes and local requirements. Consensus national standards also reduce risk for technology developers in that they have a stable set of requirements to which they can design their products. They also help to develop a significantly larger unified market on which to base their investments. National standards provide building owners and potential users of catchment systems with the confidence that the systems they install will meet local codes and operate safely and effectively.