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The San Francisco Public Utilities Commission recently had a “taste test” after a year of research to filter wastewater safely into potable drinking water, according to a story in the San Francisco Chronicle.
The commission has been capturing, treating and reusing wastewater to flush the toilets at its headquarters since the Golden Gate Avenue building opened in 2012. For its potable water research, the agency takes roughly 4,000 gallons from that supply and subjects it to a three-step purification process.
The recycled water is tested for safety before people take a drink, and it's been stripped down so much that minerals are added back in for taste.
The estimated 1,600 gallons that go through the purification process each day is carefully assessed, and in most cases, the water is returned to the agency's non-potable supply, used to flush the building’s toilets.
The recycled water project is part of San Francisco's effort to prepare for anticipated state legislation mandating that wastewater be turned into drinking water by 2023. But even then, the agency expects to conduct a lengthy public information campaign, educating residents about the process and fielding safety concerns.
City officials plan to share data on the project with their counterparts in other California cities who have an interest in purifying water running down drains and flowing through sewer systems.