Repairing, replacing and rebuilding 13,000 miles of aging and brittle water and sewage pipes and the treatment plants they connect to could cost Miami-Dade County more than $12 billion over the next 15 years.

That staggering amount — a huge jump from the billion-dollar total that had been previously discussed — was relayed to commissioners by county water and sewer director John Renfrow during a brief, lightly-attended committee meeting last week that left some stunned, and the public grabbing for their wallets.

“It’s going to take time and it’s going to take money,” Renfrow told members of the Infrastructure and Land Use Committee during an 18-minute presentation. “That’s the bad news. The good news is the shot in the arm the economy will get.”

Calling it “the topper” of all projects, Renfrow said that, when complete, the total cost will surpass the $7 billion spent to refurbish Miami International Airport and the $10 billion planned for Everglades restoration. If the $12 billion figure is accurate, it would be enough to build about 24 stadiums for the Miami Marlins, or just as many new performing arts centers.

What Renfrow did not explain to commissioners was that the $12 billion figure is not the number demanded by federal authorities who continue to grapple with the county over repairs to the aging system that must be immediately done to meet the Clean Water Act. That number is closer to $1.4 billion. The $12 billion is part of a long-range capital improvement plan that includes new sewage and water lines and new state-of-the-art plants for the six sites that now treat water and sewage.

As part of a deal to meet federal requirements, county water officials released a list of $1.4 billion in fixes the county hopes to start on soon. Among them are $948 million in fixes to three water-treatment plants in Goulds, North Miami and Virginia Key. There are another $405 million in projects throughout Dade.

The 15-year capital-improvement project calls for across-the-board fixes to water and sewage lines in neighborhoods throughout Dade. The 266-page plan calls for almost $5 billion in future bonds, $209 million in general obligation bonds, and the rest of the money to come from water bills and various grants and revenue sources such as water connection charges and rock-mining fees.

Still, the combination of short-range and long-range plans will be a bitter pill to swallow for Dade taxpayers, who Renfrow said could expect to see their water bills double or triple and their debt rise on bond payments by the billions over the next 15 years. County water bills are currently among the lowest in the nation, according to Miami-Dade officials.

“They should have started [repairs] 15 years ago,” said Sierra Club volunteer and environmental activist Blanca Mesa. “Maybe they should cancel some of the planned projects, like the tunnel or the museums. It sounds like they have an emergency on their hands.”

Though the county continues to meet with federal authorities on inking out a plan to repair the brittle piping that snakes its way mile after mile underground, Renfrow said he expects to confront commissioners in the spring with a request to sell $300 million worth of bonds to get the work started to meet federal standards.

“That’s a drop in the bucket,” Commissioner Audrey Edmonson said at last week’s meeting.