San Francisco is now the first city in the United States to mandate newly constructed buildings (over 250,000 ft²) to install onsite water reclamation systems, according to an article in The Huffington Post written by Tara Lohan. Additionally, the ordinance requires small buildings (above 40,000 ft²) to complete a reuse assessment and in the next five years will require the city “to use non-potable water for all irrigation needs and cleaning of public spaces.“ The city will no longer sacrifice drinking-quality water for uses other than human consumption. [1]
Due to California’s four year drought, aquifers are being tapped dry and reservoirs are exhausted. With the new onsite water reclamation system policy, San Francisco pioneered an efficient and affordable way to overhaul the community’s water usage. Rainwater, greywater, blackwater, and stormwater will all be repurposed for non-potable demands, including (but are not limited to) cooling, toilet flushing, and irrigation. Instead of fresh water dumped into the ocean after being treated and requiring intense energy usage, large amounts of water will be repurposed and used for non-potable water needs. The system will help reduce the overall potable water demand, sustaining the community’s water supply. [1]
Even though San Francisco passed the water reclamation mandate in July, the city has had an active water reclamation and reuse initiative dating back for years. In 2012, the San Francisco Public Utilities Commission (SFPUC) created a voluntary program for water reclamation, which accumulated 30 reuse projects, according to Lohan. [1] The SFPUC led by example and installed an onsite water reclamation system in the lobby of its Administration Building. With a capacity of 5,000 gallons per day, the system treats the building’s wastewater and produces reclaimed water for toilet flushing and irrigation – reducing the building’s water demand by over 70%. [2] The goal of installing the system was to show proof of concept for urban onsite water reclamation and reuse.
According to Paula Kehoe, SFPUC Director of Water Resources, during an interview with Lohan, “There was a lack of policy in place to allow for the collection and treatment of these kinds of water sources in private buildings. We decided to remove that barrier and let innovation occur.”[1]
In addition to requiring all new construction to install reuse systems, San Francisco has developed plans for the production and distribution of centralized reclaimed water. The project has been separated into two areas: the Westside Recycled Water Project and the Eastside Recycled Water Project. The Westside Recycled Water Project is a retrofit to an existing wastewater treatment plant, while the Eastside Recycled Water Project has two options currently being considered: (1) A large centralized reuse facility located near the existing wastewater treatment and (2) up to five smaller decentralized facilities spread throughout San Francisco’s east side. Both projects are still in the design and planning phase; the Westside Recycled Water Project will not be operational until 2019 and not until 2029 will the Eastside Recycled Water Project be operational. [3][4] Once operational, the SFPUC hopes to produce over 3 million gallons per day (MGD) of highly-treated non-potable water.[5]
The final amendment to the Non-potable Water Ordinance will go into effect November 1, 2016 and will require all new buildings of 250,000 ft² or more located outside the boundaries of San Francisco’s designated recycled water coverage area be constructed, operated, and maintained using available alternate water sources for toilet and urinal flushing and irrigation. [3]This means by November 1 2016, buildings over 250,000 ft2 across the entire city of San Francisco will be required to use reclaimed water.
With the SFPUC supplying water to 2.6 million people in the bay area, San Francisco’s move towards water reclamation will help, “expand our supply sources and make us more resilient during emergencies and times of drought.” San Francisco’s innovative policy provides validation for decentralized water reclamation and reuse and serves as a benchmark for all cities across the country.[6]
[1] Lohan, Tara. San Francisco’s Innovative Step to Save Water. The Huffington Post. http://www.huffingtonpost.com/tara-lohan/san-franciscos-innovative-step-to-save-water_b_8236072.html
[2] San Francisco Public Utilities Commission. San Francisco’s Non-potable
Water System Projects. San Francisco Public Utilities Commission. http://www.sfwater.org/modules/showdocument.aspx?documentid=5499
[3] San Francisco Public Utilities Commission. San Francisco Westside Recycled Water Project. San Francisco Public Utilities Commission. http://sfwater.org/bids/projectDetail.aspx?prj_id=310
[4] San Francisco Public Utilities Commission. San Francisco Eastside Recycled Water Project. San Francisco Public Utilities Commission. http://sfwater.org/bids/projectDetail.aspx?prj_id=311
[5] San Francisco Public Utilities Commission. Eastside Recycled Water Project. San Francisco Public Utilities Commission. http://sfwater.org/Modules/ShowDocument.aspx?documentid=2810
[6] San Francisco Public Utilities Commission. San Francisco’s Recycled Water Ordinance. San Francisco Public Utilities Commission. http://www.sfwater.org/modules/showdocument.aspx?documentid=1293