A plan to raise average water bills 50 percent by 2020 in part to fund a pipeline that will ship drinking and irrigation water from Burleson County is now headed to the City Council.

On Tuesday, the San Antonio Water System’s board of trustees unanimously approved rate increases that would finance the Vista Ridge pipeline project, which would provide up to 16.3 billion gallons per year from the Carrizo-Wilcox Aquifer.

The higher rates also would fund sewer upgrades required by the U.S. Environmental Protection Agency, a desalination project to treat brackish groundwater drawn from South Bexar County and replacement of aging sewer and water lines.

Tuesday’s vote will send the rates to the City Council for a Nov. 19 vote, amid controversy over the pipeline.

Instead of its current four-tiered rate structure, the utility would have eight tiers, based on the amount of water a household consumes per month. The more water used, the higher the price per gallon.

The small-use block, 2,992 gallons per month or less, includes 26.5 percent of SAWS users, the largest group, according to SAWS. In 2016, the price per 100 gallons for that block would be 15.11 cents. For customers using more than 20,199 gallons a month, the rate would go up to 98.18 cents per 100 gallons.

SAWS also would do away with seasonal pricing and charge the same rate for water all year.

For the average SAWS ratepayer, the new rates would mean a monthly sewer and water bill of $54.34 this year would rise to $81.73 in 2020. SAWS says an average customer uses 7,092 gallons a month.

SAWS officials say the 2016 rates will stay below what residents of Houston, Austin and Dallas pay.

They also say the 140-mile pipeline project will help to diversify the city’s water supply, which now taps eight groundwater and surface water sources, though the Edwards Aquifer supplies 90 percent of the total.

Four people opposed to the pipeline told the board it would lead to sprawl on the city’s northern fringes, deplete groundwater and create ill will in Burleson and surrounding counties.

During public comment, city resident and Alamo Sierra Club member Alan Montemayor compared the project to Los Angeles’ grab for water from the Owens River 100 years ago, a move that allowed that city’s population to swell.

“All you have to do is go to California and look at the sprawl, pollution and crime they have in Los Angeles,” he said. “I don’t want San Antonio to be like Los Angeles.”

Opponents also have cited fears based on the financial stability of Abengoa, the Spanish multinational company that will build the pipeline and sell the water to SAWS. Abengoa Water CEO Carlos Cosin attended the meeting to personally assure the board the pipeline “is one of the (company’s) most important projects.”

“We wanted to hear it, as we say in the U.S., from the horse’s mouth,” board Chairman Heriberto Guerra Jr. told him, adding that SAWS was aware of the company’s financial position when negotiations began in 2011.

Guerra also asked Abengoa Water’s local project engineer, Gene Dawson, about a recent groundwater modeling effort by hydrologist George Rice, who warned that removing so much water would cause wells to dry up and reduce flow in streams.

Dawson referred to a report by geology firm R.W. Harden and Associates presented to SAWS in 2011 as part of Abengoa’s proposal. Using the same state-developed groundwater availability model Rice used, that firm also predicted drawdowns but without the drastic effects Rice warned about.

“It’s very important we don’t confuse drawdown with depletion,” Dawson said.

Dawson also called the rate increase the “cornerstone of the project” because Abengoa must demonstrate to investors that SAWS will be able to pay the agreed-upon rates before its financial close date in early 2016.

The portion of the rate increases to pay for Vista Ridge and other water projects would rise in yearly increments: 1.8 percent in 2016, 3.2 percent in 2017, 1.3 percent in 2018, 4.5 percent in 2019 and 9.9 percent in 2020, when water from the pipeline began flowing.

These rates are caps not to be exceeded, SAWS CEO Robert Puente and other officials have said. Actual rate hikes could be lower if SAWS is able to sell some of the Vista Ridge water to other communities, if interest rates shift or if they find greater technological efficiencies that drive down costs, said Mary Bailey, controller and vice president of business planning.

bgibbons@express-news.net