Palo Alto's new plan for water management calls for building new plants, forging new partnerships and — trickiest of all — convincing residents that their wastewater is good enough to drink.

The city is now rethinking how it uses its wastewater, with the goal of converting it from a burden to a resource. The city's Regional Water Quality Control Plant, which serves Palo Alto, the East Palo Alto Sanitary District, Mountain View, Los Altos, Los Altos Hills and Stanford University, treated about 7.5 billion gallons of wastewater in 2017, of which 97 percent was dumped into the San Francisco Bay.

The remaining 3 percent was treated further and then ferried by the city's "purple pipes" to parks in Palo Alto and Mountain View, where it is used to irrigate the Shoreline Golf Links and the landscapes of corporations at North Bayshore area.

On Monday night, members of the City Council concurred with staff's assessment that given the recent drought, the raging wildfires and the general uncertainty brought about by climate change, resiliency should be at a premium. And with the Santa Clara Valley Water District looking to expand its own water portfolio, the city is hoping to make a tidy profit by making a deal with the district to build the new infrastructure.

In short, they want to take the "waste" out of wastewater.

To do that, city officials are exploring two separate strategies. One would effectively take existing recycled water and make it better while keeping it non-potable. While the council currently sells water to Mountain View, other entities — including Stanford Research Park — have been reluctant to tap into the water source because of high salt content, which they fear would damage redwoods.

Building a small plant on the west side of the regional water plant site would address that concern, said Phil Bobel, assistant director at Public Works. Using reverse osmosis to remove salt, the city would create "enhanced recycle water" that could be used principally in irrigation.

"It would feed higher quality water to our existing pipeline system so that we can get more customers along that pipeline but who aren't using it because they are concerned about salt," Bobel said.

The other, a far more ambitious, complex and controversial project, would use advanced treatment techniques to convert wastewater into the drinkable kind. Such a plant could take up to 10 years to plan out and construct, Bobel said, and it would require both a deal with the water district and — because the new water plant would have to occupy a parkland site — it would need the approval of Palo Alto voters.

Bobel said the if the city pursues a deal with the water district, a new plant to purify the water could either be constructed at the Regional Water Quality Control Plant, on a piece of parkland that was "undedicated" by the voters in 2014 or farther south, in Sunnyvale or San Jose. Under the latter option, treated water would be shipped from Palo Alto Baylands to the advanced-treatment plant.

These challenges and complexities notwithstanding, staff believes that the new system could bring great benefits to Palo Alto. It would allow the city to get paid for its wastewater; it would help the city meet its water-supply needs; and, most importantly, it would dramatically reduce discharge into the Bay and help the city meet regulatory requirements.

"We know the regulations are going to get more and more stringent over discharging to the Bay," Bobel said. "We can probably reduce us some long-term grief if we can reduce the discharge to the Bay. And sending the water south would do that."

According to Public Works staff, the plant has the treatment capacity to produce 4.5 million gallons per year of non-potable water.

The city and water district have been talking about a possible deal for months. Both Palo Alto and the water district have representatives on the Joint Recycled Water Advisory Committee, which also includes officials from Palo Alto, East Palo Alto and Mountain View.

Garth Hall, deputy operating officer at the water district, said the district is looking for new supplies to meet an expected rise in countywide demand for water.

"We know from our planning that we have additional needs in 2050 and beyond that can't be directly served by imported water. We have to look at drought-proof sustainable supplies," Hall said. "And we know the City Council, like our district, has sustainability as one of its missions."

One point of negotiations will be the length of the contract. Bobel said he expects the agreement with the water district to cover a period of about 40 years, a period that several council members suggested was too long.

"We can understand why it has to be that long," Bobel explained. "If the district is going to spend big bucks either building the water plant and/or a pipeline system south, they've got to have this exist for long enough to recoup the investment."

While council members had some reservations about the potential terms with the county — including the prospect of locking in a rate for too long a period — they generally supported the idea of turning recycled water into potable water. Councilman Tom DuBois, who sits on the Joint Recycled Water Advisory Committee, argued that the city should consider ways to diversify its water supply over the long term.

"I believe as a council we should really look at coming together and analyzing how we can get a large potable water treatment plant in Palo Alto that helps us decrease Hetch Hetchy water over 40 years," DuBois said.

Councilman Cory Wolbach, who also serves on the committee, concurred that "recycled water is the future." He lauded the goals of supporting neighbors and promoting sustainability but said his top priority is ensuring a secure supply for residents.

"We have to do everything we can to guarantee that our local community will have access to safe drinking water in perpetuity," Wolbach said. "For me, that value has primacy in all these discussions."

Several residents, including former mayors Pat Burt and Peter Drekmeier, also spoke in favor of exploring new ways to purify and reuse water. Burt pointed to the recent string of devastating wildfires as evidence that the city is already facing the impacts of climate change. In addition to threatening residents, the fires are decimating the forests that are essential to protecting snowpacks. This recent trend, Burt argued, underscores the importance of securing stable water supplies.

"Reducing our reliance on distant and vulnerable supplies makes us more sustainable and more self-reliant," Burt said.

In addition, he said, the plant could be the first to use 100 percent carbon-free electricity, a key feature for such an energy-dependent project.

Drekmeier, policy director for Tuolumne River Trust, made the case for "advanced purified water." In most communities, it would actually be an improvement over their current tap water.

"We're very fortunate that we get this pristine snowmelt from the Tuolumne River in Yosemite National Park," Drekmeier said. "But I think most people would agree that our drinking water is too high quality for flushing toilets and watering lawns. We need to diversify."

Like others, he acknowledged that the city would have to fight the "yuck" factor, but suggested this challenge is not insurmountable.

"A few years ago, we served beer made from advanced treated water at the Silicon Valley Water Conservation Awards," Drekmeier said. "It was more popular than the tap water."