Buildings — especially commercial-use buildings — waste a lot of water. Or rather, they fail to reuse water when it makes sense to. There’s no need to use clean drinking water for something like flushing a toilet or watering a lawn, and yet potable water is used every day for those purposes.
There are systems now cropping up across the country from New York City to Minnesota to San Francisco that capture water from “alternative sources” — think rain and sewage versus reservoirs and wells — for non-potable uses. And instead of shuttling the water to central locations, it happens on-site so that water can be used multiple times before it leaves a building.
But there are some hurdles in the way, and a big one from a private perspective is uncertainty, according to the San Francisco Public Utilities Commission’s (SFPUC) Paula Kehoe.
“If [vendors] know to build their treatment systems to X standard, it certainly makes it easier from a vendor perspective, from a developer perspective and from a [regulator] perspective,” she said.
That’s where players like public utilities commissions can come in handy, Kehoe said. While there are plenty of standards at various levels of government for the quality of gray water — secondary-use water that comes from systems like laundry machines — those some government entities often lack standards for other types of water. Black water, for instance, includes sewage from toilets, but can still be treated and reused.
While the water is used for non-potable purposes, Kehoe said it still needs to be held to a certain quality standard because it’s accessible to people. So if PUCs can work together with cities to set standards for those alternative water sources, as well as work with developers to ease their systems toward installation, it makes it much easier to see those projects through to completion.
“All the rules and regulations are in place to basically speed the process for other developers,” said Allison Kastama, a spokesperson for SFPUC.
And according to Kehoe, the potential for such systems are big. SFPUC has installed a black water treatment system in its own building that has helped it reduce its consumption of potable water by 65 percent. For commercial buildings like theirs, she said customers can reduce their potable water consumption by as much as 95 percent — but that’s an upper boundary, and most projects will fall somewhere below that. For multi-family housing units, which use more water for potable uses, the typical reduction is closer to 50 percent.
“It’s a concept of finding the right water for the right use,” Kastama said. “For toilet flushing, you don’t need to use drinking water.”
Since the commission began working to encourage on-site treatment in 2012, it has seen 15 systems installed throughout the city. Another 28 projects are in the design or construction phase. The developments are being driven by the adoption of a city ordinance requiring all new developments of 250,000 square feet or larger to have on-site treatment systems — a rule with a two-part phase-in that will be completed in November.
While Kehoe said the initiative wasn’t in response to California’s historic drought, the project has aimed for water conservation when the state needed it most. Facing mandatory cutbacks from the governor, water districts across California have begun looking for ways to build new systems or enhance existing ones that allow for long-term conservation. In Los Angeles, that means connecting pieces of a robust but at times disjointed system of water-controlling infrastructure. In the Central Valley, it has meant building experimental systems to channel water into agricultural fields where researchers hope it will replenish underground aquifers.
But when it comes to on-site treatment, SFPUC isn’t just focusing on San Francisco. Together with the nonprofit Alliance for Water Efficiency (AWE), SFPUC won Imagine H20’s first-ever California Water Policy Challenge at the end of January. Imagine H20, another nonprofit that seeks to accelerate the deployment of water technology, is offering up to $25,000 in support to SFPUC and AWE to help them conduct outreach to stakeholders throughout the state to help them similarly smooth out the regulations for on-site treatment systems.
SFPUC is also looking outside California. Government entities across the country, including New York City and the states of Minnesota and Washington, have their own projects underway. Working through the National Water Research Institute, SFPUC has begun collaborating with some of those other government entities to further refine the standards for on-site treatment systems. That way, other public servants looking to foster on-site treatment installations in their jurisdictions can look to easy examples and implement them without having to start from scratch.