By Paula Kehoe
Reimagining urban water systems demands collaboration, consistency, and crosscutting ideas. Utilities have an important leadership role in actively promoting integrated water resources management and building an enabling environment for water supply diversification. Onsite non-potable water systems (ONWS) represent a significant opportunity to transform the way water is managed, highlighting the role of technology and innovation. For example, onsite water systems can reduce potable water use by approximately 25 percent in residential buildings, and up to 75 percent in commercial buildings. By capturing water sources such as stormwater, rainwater, graywater, blackwater, and foundation drainage, buildings can reduce the use of precious drinking water supplies for uses such as toilet flushing and irrigation.
In September 2012, the City and County of San Francisco adopted the Onsite Water Reuse for Commercial, Multi-family, and Mixed Use Development Ordinance. Commonly known as the Non-potable Water Ordinance, it allows the collection, treatment, and use of alternate water sources for non-potable applications in individual buildings and at the district-scale. In 2015, San Francisco added a mandatory requirement for development projects over 250,000 square feet to install and operate an onsite non-potable water system to treat and reuse available graywater, rainwater, and foundation drainage for toilet and urinal flushing and irrigation. New developments of 40,000 square feet or more are required to prepare water budget calculations assessing the amount of water available for potential treatment and reuse.
In addition to our work in San Francisco, SFPUC is working on state and national efforts to establish guidance and policy frameworks to help local jurisdictions overcome barriers for onsite water reuse. The National Blue Ribbon Commission (NBRC) for ONWS was established to craft model state policy and develop resources to demonstrate how onsite non-potable water systems can help utilities meet One Water goals. Chaired by SFPUC, the NBRC represents 12 states and the District of Columbia, and is a coalition of public health agencies and water and wastewater utilities advancing the safe, practical, and sustainable implementation of ONWS. The NBRC has made significant research contributions and advanced policies and regulations for onsite water reuse.
The NBRC’s latest research project is a guidance manual and training for system designers, regulators, program administrators, system owners, and operators involved in implementing onsite reuse. The manual translates the risk-based public health guidance into effective design, operation, and regulation of ONWS. This manual not only helps with capacity building, but it is also designed for use in a training session with a combination of interactive presentations and workshop-style problem solving exercises. Together with the many existing resources, there is a solid foundation for developing and implementing onsite water systems that comply with the risk-based health standards and are protective of public health.
Other recent NBRC resources include A Guidebook for Developing and Implementing Regulations for Onsite Non-potable Water Systems and Making the Utility Case for Onsite Non-potable Water Systems, both of which are valuable resources for utilities and municipalities seeking to implement onsite water reuse programs. These efforts contributed to a fundamental shift in the perspective of many participating agencies, which now have the appropriate framework and tools to develop regulations. California, Colorado, Hawaii, Washington DC, and Minnesota have been able to move forward with regulations or policies supporting onsite reuse within the last few years, while others, including Washington, Oregon, Texas, and Alaska, are considering similar steps forward.
With the WateReuse Association providing the administrative management of the NBRC in collaboration with founding partners The Water Research Foundation, US Water Alliance, and SFPUC, this group will continue to shape the national discourse around water reuse. Additionally, it will seek opportunities to support the use of alternative sources of water and deployment of ONWS through sharing of information and educational materials, technical assistance, research, and policy advocacy.
Paula Kehoe is the director of Water Resources with the San Francisco Public Utilities Commission (SFPUC). She is responsible for diversifying San Francisco’s local water supply portfolio through the development and implementation of conservation, groundwater, and recycled water programs. Paula spearheaded the landmark legislation allowing for the collection, treatment, and use of alternate water sources for non-potable end uses in buildings and districts within San Francisco.