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Overcoming the Challenges of Small-Scale Water Recycling

San Francisco is helping to grow adoption of onsite nonpotable water reuse systems by requiring them in large new buildings. Now there is interest in a statewide regulation to streamline permitting while ensuring health and safety.

Written by Tara Lohan Published on Read time Approx. 7 minutes
Aerial view of the South of Market neighborhood in San Francisco on an overcast California day. The Moscone Convention Center (left) is being expanded and will include an onsite water treatment system for nonpotable water.Smith Collection/Gado/Getty Images

In downtown San Francisco, a mixed-use 800ft tower nearing completion at 181 Fremont St. features a water treatment system that will provide 5,000 gallons a day of recycled water captured from the building to be used for toilet flushing and irrigation. That will help save an estimated 1.3 million gallons of potable water a year.

Just down the street, the recently expanded Moscone Conference Center has installed a system to collect and treat foundation drainage, otherwise known as “nuisance groundwater,” that will be used for toilet flushing and irrigation as well by the city’s Department of Public Works for street cleaning.

Both buildings are among 82 proposed or completed projects in San Francisco that are using decentralized, onsite water-recycling systems to capture and reuse water that would otherwise flow down the drain or run off rooftops to city sewers or into the San Francisco Bay. The treated water that’s captured isn’t used for drinking, but for nonpotable purposes such as flushing toilets and urinals, irrigating landscapes, supplying cooling systems and even generating steam power. In commercial buildings, about 95 percent of water used is generally for nonpotable purposes. In multifamily residential buildings, it’s 50 percent.

As interest in recycled water grows in California and across the United States, more building professionals are considering these decentralized systems. Up until now, a lack of health and safety regulations at the national and state levels has made the permitting process tricky and slow going. But bottom-up pressure may help create needed regulations.

“I think 2017 is a real changing year for water – it’s on everyone’s radar now,” said Piper Kujac, director of project management at Urban Fabrick, a sustainability and design firm that worked on 181 Fremont St. “I had to start the conversation in years past, and now we have building owners approaching us. It’s telling of what’s to come. I think because of the momentum we’ve gained through this drought, people are aware that we need to be more prepared for future droughts and more resilient.”

A Mandate in San Francisco

The city emerged as a leader in onsite reuse systems in the U.S. after the San Francisco Public Utilities Commission (SFPUC), the local water utility, started a voluntary program in 2012 to provide expertise and funding for builders that wanted to incorporate onsite nonpotable reuse into new construction projects.

181 Fremont Street in San Francisco is a mixed-use high-rise with an onsite water recycling system estimated to save 1.3 million gallons of water a year. (Jay Paul Company, Heller Manus Architects and Steelblue)

In 2015, the city moved to mandate that new construction over 250,000 square ft collects and treats rainwater, gray water (wastewater from bathroom sinks, showers and washing machines) or foundation drainage for uses such as toilet flushing and irrigation. It also gave building managers the option to collect and treat black water (wastewater from kitchen sinks and toilets) and stormwater, if desired. It was first mandated only in a certain section on the east side of the city where there was some existing “purple pipe” infrastructure for recycled water already, but has since expanded citywide.

“To do a nonpotable program is based on local context – this program works for San Francisco and it works within our water management strategy and water portfolio,” said Paula Kehoe, director of water resources at SFPUC. “We see decentralized systems as complementary to our centralized system – they integrate.” The city is currently building a centralized recycled water facility on the west side of the city, and most of the development with onside reuse is on the east side of the city.

But for some communities, decentralized systems may not work or be appropriate in the local context or management strategy, she says. For example, if a city has its own centralized water-recycling center, it may not want individual buildings to capture and treat their own gray water or black water.

But for communities that do want to move forward to enable and encourage onsite reuse, it can be a regulatory slog. “It takes time and it involves interagency coordination,” said Kehoe. For example, San Francisco’s ordinance involved the city’s Department of Public Health, Department of Building Inspections, Department of Public Works and SFPUC. And San Francisco has it easy because it has only one water utility and is both a city and county. Some municipalities may have multiple water agencies as well as various city and county agencies that would need to be involved.

This process would be easier for communities if there were established health and safety standards from the state for onsite nonpotable reuse, but so far they’re lacking.

“We think that from our perspective, if there is clear guidance and regulations that the state establishes, it would make it easier for communities that want to pursue local programs to oversee and manage decentralized water systems,” said Kyle Pickett, managing principal at Urban Fabrick.

Those regulations could be on the way, but how long it will take is unclear.

“Of course we want utility-scale water recycling, but we also want onsite water reuse and we want to make it easier and available to people,” said California state senator Scott Wiener who was behind San Francisco’s nonpotable reuse ordinance in 2015 when he was a member of the city’s Board of Supervisors and this year as a state legislator introduced a bill to require California to set health and safety standards for onsite reuse. The bill he introduced would “give confidence to communities that they can move forward with a local program,” Wiener said. “The state should have set these standards a while ago, but they haven’t.”

Wiener’s legislation stalled in committee this term, but he says he has been working with the State Water Resources Control Board to tweak the bill’s language and will keep pushing it in 2018.

The Road Ahead

While there are no national or state regulations for onsite nonpotable reuse yet, there is a growing community of professionals sharing resources and expertise. SFPUC’s Kehoe chairs a National Blue Ribbon Commission for Onsite Nonpotable Water Systems, which recently produced a guidebook on water quality standards and management of onsite reuse systems. The commission was established by the U.S. Water Alliance, and it convenes more than 30 water and health professionals from across the country.

“I think the regulatory guide is a start because it encourages cities to have some framework to go on to start developing their own requirements,” said Kujac.

Enzo Manca, director of engineering, monitors the computer system in the graywater treatment room that collects, filters and chlorinates the reclaimed graywater on the lush grounds of the Hotel Bel-Air in Los Angeles. (Al Seib/Los Angeles Times via Getty Images)

Other efforts are underway, too. Urban Fabrick’s nonprofit arm, the William J. Worthen Foundation, will be releasing a practice guide on January 19 aimed at giving design professionals information about onsite reuse. “We’re taking highly technical information and distilling it down to easily digestible chunks of text and infographics so they can become better informed about water reuse,” said Pickett.

Among architects, Pickett says he saw the conversation begin to shift around water reuse about four years ago. At the time, Urban Fabrick cofounder William Worthen had written an article in Architect Magazine encouraging architects to start thinking about water early in the design process.

“If the first time you seriously discuss water with your client and plumbing engineer is at the time of bathroom and kitchen fixture selection, or when running the calculations to confirm how many LEED [green building] credits you get, you are very likely missing some interesting opportunities to collaborate and engage with your client and project team on the subject of water,” Worthen wrote.

And even though the conversation is shifting among architects and other design professionals, many people are still not familiar with how water recycling systems work. When designing 181 Fremont St., Pickett says they initially had pushback from their client when they proposed an onsite reuse system.

“It really took the client, the sustainability consultant and a couple other members of the project team to physically see what these systems do and that they don’t smell and that they are safe and that it is a proven technology,” says Pickett. “We’re just not familiar with it in the U.S. It became an education issue to go from ‘yuck’ to ‘yeah.’”

But there is still a long way to go with water recycling – both for onsite systems and large centralized ones.

“We don’t do nearly enough water recycling in California, honestly, it’s embarrassing how far behind we are compared to Australia, Israel and other places with very arid environments,” said Wiener. “We have a long-term structural water shortage and we need to modernize our water system and drag it out of the 1850s. Water recycling is a critical aspect of modernizing our water system.”

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