ARCHITECT: On the Progress and Promise of Water Reuse
By Mary Catherine O'Connor
Water management is a critical component of resilient design yet building codes and regulations typically assume a centralized, utility-provided water delivery and wastewater collection. Introducing decentralized systems to capture and reuse water has traditionally resulted in a regulatory quagmire.
The good news is that codes are changing to accommodate decentralized systems. Since 2012, when ARCHITECT last reported on water reuse systems, some municipalities passed important regulations to govern the design, permitting, and safety of graywater reuse systems. In fact, the city of San Francisco now requires any building 250,000 square feet or larger to install and operate an onsite non-potable water system to treat and reuse available graywater, rainwater, and foundation drainage. Seattle also recently adopted a rainwater capture and reuse mandate for large buildings.
to help municipalities craft regulations around the design, permitting, testing, and safe operation of water reuse systems. These include a guidebook for implementing regulations for non-potable reuse systems, model language for a local water reuse ordinance, and model language for a state ordinance.
Additionally, the William J. Worthen Foundation, a nonprofit sustainability and design research firm based in San Francisco, released a preliminary non-potable water reuse practice guide to help design professionals understand the pros and cons, cost, and regulatory considerations of water reuse systems (a final draft is due next year).
Clark Brockman, AIA, a SERA Architects partner based in San Mateo, Calif., says these resources represent “sea-change events” because they provide regulatory and professional frameworks for implementing non-potable reuse systems. The practice guide in particular, he adds, was written by design professionals who have been through the onsite reuse wringer.
From Building to a Waterworks
Getting a project approved to treat graywater for potable applications still requires trailblazing. Just ask Greg Mella, FAIA, the Washington, D.C. based–director of sustainable design at SmithGroupJJR, the firm behind the Brock Environmental Center. Early in the design process, SmithGroupJJR and the CBF decided to install an onsite purification system to reuse graywater for handwashing. But under the U.S. Environmental Protection Agency’s Safe Water Act, water that comes into direct contact with humans has to be treated to a drinking water standard. And because the community-scale building would serve hundreds of people each year, Mella says it needed “to become a public waterworks in order to serve water to the public,” which required permitting from both the Virginia Department of Health and the Office of Drinking Water.
Prakash PatelTwo 70-foot-tall wind turbines supply nearly half of the Brock Environmental Center's energy.
But the biggest regulatory burden the team faced was the water quality testing requirements. Virginia state law, which is based on EPA water quality standards, requires potable water sources to be monitored daily to ensure safety. CBF astutely sent the building’s facility manager to a six-day class at the local university to earn a water quality inspection certification; contracting a waterworks engineer would have cost 30 times more. A local engineer does perform monthly and annual water quality tests.
The Brock Center collects rainwater in two cisterns onsite and sends it through a treatment skid designed by SmithGroupJJR and Baltimore-based Biohabitats. The water is twice disinfected with ozone and ultraviolet light, which Mella says is enough to render it potable, but Virginia state law requires the water to also be treated with chlorine in order to facilitate daily testing (which measures residual chlorine levels). Mella has submitted an appeal to the Office of Drinking Water, citing health and safety concerns related to having a tank of concentrated chlorine onsite. Instead, he wants to measure residual ozone as an alternate testing method. The Commonwealth has yet to respond.
Once the treated rainwater is used, the now-graywater is sent to an infiltration garden, where it replenishes the site's aquifer.
Courtesy SmithGroupJJRWater management systems, Brock Environmental Center
The Jurisdictional Jungle
Despite the emergence of municipal frameworks for non-potable applications for graywater, getting projects permitted can still be a heavy lift in many parts of the country. Architects and designers typically turn to their local municipalities to seek permits for graywater or blackwater reuse projects, as they would for other building systems. But without clear water reuse rules and standards, municipalities have to consult with multiple agencies because reuse systems fall under building, plumbing, and health codes, while local jurisdictions manage building codes, public health is a state-level agency, and water utilities may be managed at city, county or region levels.
For example, for a commercial building in Portland, Ore., graywater captured from showers falls under the plumbing code, but if it is diverted for irrigation, it falls under the state’s Department of Environmental Quality. The plumbing code covers harvested rainwater, but if it is captured for potable applications, it falls under the state’s Department of Health and Human Services.
San Francisco is an exception, Brockman notes. “The city and county of San Francisco, and its water district and [water and sewer] utility all share the same boundary, which is very rare.” One board of supervisors oversees the building, water management, and the public health department (responsible for the safety of the drinking water), which helped to streamline the development of a non-potable onsite water reuse ordinance. The ordinance, included in the San Francisco Health Code since late 2012, allows “the collection, treatment, and use of alternate water sources for non-potable applications in individual buildings and at the district-scale.”
But head south to Los Angeles, and the interplay between city and county jurisdictions is far less straightforward. As a result, the director of L.A. County Department of Public Health’s Environmental Protection Branch, Jacqueline Taylor, has been working closely with the director of water resources of the San Francisco Public Utilities Commission (SFPUC), Paula Kehoe, and 30 other representatives from municipalities, water utilities, and public health agencies nationwide to advance the model local and state water reuse ordinances that the NBRC has just released. Taylor says the county currently reviews up to 250 water reuse project proposals each year, but because the county comprises 85 cities with varying degrees of experience—let alone interest—in supporting water reuse projects, graywater reuse has been a complex issue for the health board to navigate.
Some municipal leaders are motivated to support decentralized water management due to ancillary benefits, such as reducing the volume of wastewater sent to a city’s sewers. For the three-building development Hassalo on Eighth in Portland, Ore., “the city wanted to densify and wanted to address a sewage overflow [problem],” says Pete Muñoz, senior engineer at Biohabitats. Even with an onsite water treatment system, buildings are required to plumb connections to Portland’s wastewater system—which in the case of Hassalo on Eighth would have cost around $4 million. But because the project would significantly reduce flow into the sewers by collecting, treating, and reusing all graywater and blackwater—about 45,000 gallons daily—Portland credited the developers $1.46 million.
Courtesy BiohabitatsWater treatment system, Hassalo on Eighth, in Portland, Ore.
Focus on Water Quality
The treated water from the Hassalo on Eighth complex meets the State of Oregon’s Class A reuse standards, but Pat Lando, executive director of Portland, Ore.–based Recode, thinks those standards are overkill. Since 2015, the International Residential Code, the International Plumbing Code, the Uniform Plumbing Code, and the International Green Construction Code have all specified a wastewater treatment standard—NSF/ANSI 350—for water reuse non-potable purposes, such as irrigation or toilet flushing. But Lando considers the purification levels and monitoring schedules that the NSF 350 standard requires “a higher level of treatment than is necessary.”
Brockman, Muñoz, and Lando are pleased that the model state and local ordinance language that the NBRC recently released uses a performance-based purification criteria based on the pathogens its panel of experts determined to be the greatest concern to human health in onsite non-potable water systems. Lando says the transition to this quality criteria will also lower the maintenance and operational costs of reuse systems.
Muñoz says the NBRC’s work “will give the regulatory community a framework, give the design community tools, and give clients and end users a reasonable monitoring framework.” Of course, this presumes states and municipalities adopt or at least integrate the language into their regulations, but Lando is encouraged that many or all of the more than 10 states considering the ordinance will adopt it.
Gray to Black
In early 2018, SFPUC will take the next important step toward a future where water recycling can come full circle. A number of wastewater utilities, including ones in Colorado, Singapore, California, and Australia, have tested or deployed systems that purify graywater or blackwater for drinking water. In the U.S., only one decentralized wastewater-to-potable water system has been deployed, in Ohio.
In a nine-month pilot project called PureWaterSF that starts early next year, SFPUC will use microfiltration, reverse osmosis, and advanced oxidation with ultraviolet light to bring wastewater produced at its headquarters to federal and state drinking water standards. Though the water will only be monitored and not consumed, Kehoe says that this project represents an important first step. Studies such as these will help the NBRC to develop model regulations or policies for decentralized potable reuse systems, she says. “It’s a matter of time.”
Note: This article has been updated since first publication to clarify the water treatment system at the Brock Environmental Center; to correct the cost of Hassalo on Eighth's sewer connections; to note that Greg Mella is a Fellow of the AIA; and to reference the EPA's Safe Drinking Water Act.