In 2012, San Francisco began regulating onsite non-potable water systems in buildings and later required them in new construction.
Today, there are 80 such systems operating or under development that will save a combined 89 million gallons of drinking water annually. By comparison, San Francisco residents use around 65 million gallons of potable water each day.
To boost this water conservation effort, which grew in popularity during the last California drought, the San Francisco Public Utilities Commission is voting Tuesday on a proposal to expand its grant incentive program for building owners to install non-potable water systems to include smaller buildings and also breweries.
The systems capture rainwater or water from such things as bathroom sinks or toilets then treat it for reuse in toilet flushing and irrigation.
Under the proposal, projects that replace at least 450,000 gallons of potable water annually could receive up to $100,000 in grant funding. “This modification will allow buildings with existing dual-plumbing and smaller buildings that are voluntarily installing an onsite non-potable water system to be eligible for grant assistance,” according to a memo from Paula Kehoe, the Director of Water Resources with the San Francisco Public Utilities Commission.
Currently, projects that replace at least one million gallons of potable water per year can receive up to $250,000 in grant funding and those that replace at least three million gallons of potable water per year can receive up to $500,000.
Breweries were added to the mix after SFPUC staff paid a visit to “Lagunitas Brewery in Petaluma and learned about the system they use to capture and reuse water on-site; we wanted to make similar opportunities available to breweries in San Francisco,” said Suzanne Gautier, a spokesperson for the SFPUC.
The proposal would “allow breweries to collect, treat, and use brewery process water for non-potable applications such as tank rinses, bottle rinses, packaging, clean-in-place, and production.”
The SFPUC created the grant program in June 2012 and has so far provided $2 million in grants to five projects.
The Salesforce Tower at 415 Mission St. received a $250,000 grant from the SFPUC for a blackwater treatment system, one that treats raw sewage, “to meet the building’s toilet flushing, cooling tower make-up, and irrigation demands.” The system is scheduled to begin operation in early 2019.
In 2015, San Francisco required that new construction of 250,000 square feet or more use alternate water sources for toilet flushing and irrigation under legislation introduced by then Supervisor Scott Wiener.
Wiener, now a state senator, has proposed advancing water re-use throughout California. In February, he announced Senate Bill 966 that would require the State Water Resources Control Board to create statewide regulations for onsite treatment and reuse of non-potable water to encourage local jurisdictions to adopt programs like San Francisco’s.
Harlan Kelly, SFPUC’s general manager, said in a February statement that the state bill is “particularly significant as onsite non-potable water reuse becomes an increasingly important strategy for communities to diversify their water supply portfolios and effectively deal with droughts.”
Of the 80 systems in various completion stages on record with The City, nearly all reuse rainwater while 14 reuse graywater, which is wastewater from clothes washers, bathtubs, showers, and bathroom sinks, and two blackwater, according to an SFPUC report.
“Replacing the demand for toilet and urinal flushing with non-potable water can offset approximately 25 percent of the total water demand in a residential building and up to 75 percent of the total water demand in a commercial building,” according to the SFPUC’s non-potable systems guidebook. “Other potential non-potable water demands include irrigation, cooling/heating applications, process water, and clothes washers. Using onsite water systems to meet these demands can decrease potable water use anywhere from 50 percent to 95 percent.”