The epic drought we’re having in California means that every drop of water conveyed from rivers to cities must be scrutinized as to whether it’s being put to its highest and best use. While we all have our fingers crossed that this year’s El Nino might bring us a Goldilocks-perfect amount of rain and snow — not too much, not too little — hope is not a strategy. Today’s water emergency must be thought of as a preview of the future. Climate change could easily bring more severe, frequent droughts to California in the future, and our historical climate record shows periods of “megadrought” lasting 100 years or more.
By 2040, we will also add 8 million people to California — all of whom will require water. In the absence of action, today’s drought is tomorrow’s structural water deficit: There won’t be enough to go around, even if we start having normal water years again. What we need is a pathway to sustaining the conservation savings we’ve managed to make this summer — one that makes the most of every drop we get. (As we found in our 2013 report Future-Proof Water, the Bay Area’s urban water demand could increase over 40 percent by the end of the century.)
As we have written about many times, we need to both build new supplies and reduce water demand through techniques like conservation, efficiency, pricing, submetering, trading, banking, recycling and reuse. Many of these tools are more for utilities to deploy than consumers. An outstanding Bay Area example is the Santa Clara Valley Water District’s Advanced Purification Facility, which treats wastewater effluent to drinkable standards. Now San Francisco has upped the ante on what building owners and developers can do themselves to improve water reliability and reduce our future structural water deficit (and likely, their own water bills). Changes to the city’s nonpotable water program, approved this month, will provide grant funding for existing buildings to install onsite water treatment and reuse systems — and for buildings to connect to each other and recycle water as a district.
San Francisco’s nonpotable water program was first approved in 2012 and strongly supported by SPUR. The city passed an ordinance that clarified the permit process for water recycling at the building scale, and the San Francisco Public Utilities Commission (SFPUC) created a grant program to allow commercial building users to make use of available nonpotable water — such as rainwater, graywater and foundation drainage — for nonpotable uses, such as toilet flushing and irrigation. Such onsite water reuse systems can reduce an average commercial or mixed-use building’s potable water demand by 20 to 75 percent. This voluntary program has been a tremendous success, with over 30 projects in the city either in design, construction or operation to date. The ordinance was expanded in 2013 (again with SPUR’s support) to create a permitting process and grant eligibility for district-scale projects, where two or more buildings would voluntarily share non-potable water resources. District-scale water reuse is seen as a key opportunity to advance sustainability in existing urban neighborhoods, such as Central SOMA in San Francisco.
In July of this year, city supervisors and the mayor made nonpotable reuse a requirement for new buildings over 250,000 square feet — the first of its kind in the nation. New large buildings must use available onsite sources for nonpotable applications, and buildings over 40,000 square feet must use a water budget calculator to evaluate nonpotable reuse options (although there is no actual requirement to implement it).
This month, in recognition of the new requirements, the SFPUC altered the grant program to base eligibility on water use rather than building size. It also extended grant resources for existing buildings to build onsite reuse systems — a category excluded from previously available grant funds. There are a lot of buildings in San Francisco that could benefit from additional resources to build treatment systems for recycled water. That’s because since 1991, most large buildings in the Reclaimed Water Use Zone — which includes much of downtown, SOMA and the eastern waterfront — have been required to install purple piping for recycled water. Since the city has no plans to supply these buildings with recycled water for at least the next 10 years, this grant program could help make good on the substantial private investment that has already been made in a recycled water network by supporting the costs to put treated water into the purple pipes.
Finally, the grant program expansion will now extend resources for existing or new buildings to connect to each other, creating a district-scale system for recycling water. We think that sharing and recycling water resources across property lines may have the best economies of scale for water treatment and the highest potential to offset potable water use (especially where existing buildings have installed purple pipe but haven’t developed a source to supply it, or a connection to each other). For example, one building may have significant foundation drainage that it currently pumps into the sewer system; an adjacent multi-family residential building may be able to use that water for toilet flushing, or a park across the street could use it for irrigation. Some of the city’s large neighborhood-scale projects, such as Parkmerced, India Springs and Mission Rock, could benefit more from district-scale rather than building-scale water facilities.
SPUR is enthusiastic about the potential of these changes to the program — and we think there’s even more the city could do. For example, the city could fund or develop district-scale water budgets in neighborhoods around the city, especially those that expect significant new development in the next five years. These budgets would weigh existing infrastructure, facilities and water resources to identify and match supplies and potential demand for nonpotable water. An in-lieu fee option could be considered for large projects (which are now required to build onsite systems) to expand the financial capacity for off-site district-scale facilities that might be strategically located and aggregate demand.
The SFPUC has attracted national attention, and a Good Government Award from SPUR, for this innovative program: New York City, the State of Washington, Silicon Valley and others are considering what they can learn from San Francisco to support building and district-scale water reuse in their jurisdictions. While we all need to keep saving water — and will need to even once it starts raining again — San Francisco can be proud of how local innovation and public support for water resilience is catalyzing private investment in sustainable infrastructure. Expanding building and district-scale water re-use could transform urban water demand — and especially its growth trajectory — for the Bay Area and beyond.