*Correction appended

SAN ANTONIO — At a City Council hearing here on a $3.4 billion contract that would pipe 16 billion gallons of water a year into the city, residents called for more time before the council votes to buy some of the most expensive water ever sold in Texas.

"The scope and price tag of this particular deal make it different than other day-to-day decisions,” said Diane Duesterhoeft, a leader with the COPS Metro Alliance, a San Antonio coalition of congregations, schools and unions. “There must be time for a deliberation, healthy debates and democratic participation.”

The San Antonio Water System board unanimously approved the project at the end of September, and Wednesday was the City Council's first public hearing on the project. Its members could vote on the pipeline as early as this month.

Called the Vista Ridge pipeline, the venture is a private project spearheaded by two companies — Austin-based BlueWater and the Spanish company Abengoa. The pipeline would serve 162,000 new families, and San Antonio residents would see a water rate hike of about 16 percent. The pipeline would begin pumping water into the city by 2020.

Allen Montemayor, who has lived in San Antonio for nearly six decades, said he is concerned the pipeline would drastically increase water rates beyond 16 percent.

“I think that’s a complete bogus number,” Montemayor said. “All this pipe is going to do is facilitate growth in the city of San Antonio. What we want is a good place to live — we don’t want a sprawling Los Angeles."

But San Antonio Water System President Robert Puente said the 16 percent is an average, and some residents could see lower rate hikes than that.

“We understand this is a hefty hike, and we want to mitigate those rates as much as possible,” Puente said. “The time has come to act now. ... We have a great opportunity in front of us.”

Responding to criticism that the process has been too fast and not transparent, Puente said the board first asked for proposals three years ago. There have been more than 70 public meetings, he said.

“We had open meetings for our negotiations,” Puente told the City Council. “I have personally sat down with a lot of the opponents behind me and tried to explain this project.”

Until just a few months ago, Puente cautioned against the contract — but reversed his decision recently after changes were made to the proposal.

Proponents of the pipeline say it would expand the city’s water supply beyond the Edwards Aquifer and help guarantee water for a growing city. The Vista Ridge pipeline was met with droves of support Wednesday night from leaders of the real estate, medical and business communities, who said the pipeline would increase the city's water supply and keep jobs in San Antonio.

Jim Reed, president of the San Antonio Medical Foundation, called on the City Council to approve the contract because of the city’s dependency of a single aquifer.

“Over the years we have watched as opportunities to obtain secure and adequate water supplies switch away for various reasons. We now have the chance to change that,” Reed said.

Duane Wilson, the president of the North San Antonio Chamber, also called for the City Council to vote for the pipeline.

“I’ve seen all the lakes around Texas go dry, I’ve seen a lot of communities in a lot of trouble,” Wilson said. “This is a critical need for economic development.”

Opposing the pipeline, Duesterhoeft raised concerns about how the water rate hike could affect lower- and middle-class residents. She asked the San Antonio Water System board to revisit the rate structure and said she hoped City Council members would hold meetings in each of their districts.

"Real public dialogue has been largely absent from this process," Duesterhoeft said. "Making presentations to the chamber of commerce is not enough. Opening the doors to the public and asking them to sit quietly in the back is not enough."

Disclosure: The San Antonio Water System is a corporate sponsor of The Texas Tribune. A complete list of Tribune donors and sponsors can be viewed here.

Correction: An earlier version of this story misidentified San Antonio Water System Board President Robert Puente. It also misspelled the name of the Spanish company Abengoa. Finally, the story gave an incorrect year in which the Vista Ridge pipeline would begin pumping water into San Antonio; the correct year is 2020.