Though the county’s proposed budget for the new fiscal year that begins Oct. 1 does not provide for any water-rate increases, it does project a 9-percent rate hike in 2013-14 — followed by an additional 6 percent increase each year over the next three years.

At a preliminary budget hearing earlier this month, Commissioner Lynda Bell questioned whether the county should consider easing residents into the higher rates beginning this year.

“I’d much rather see it gradually than just one big hit,” she said.

County Mayor Carlos Gimenez said it will likely take a combination of water-bill hikes and bonds to cover any agreement with the feds. The county has scheduled three community meetings for next week, and Renfrow said he expects a full plan signed off by the federal government that he can present to commissioners by March.

“We don’t have the complete picture yet, but we’re getting there,” Renfrow said.

The city of Cincinnati, which recovered from a similar problem about a decade ago, spent $1.5 billion on fixes after negotiations with the federal government. The city also agreed to set up a victim’s compensation fund, in which the water and sewer department agreed to pay for injuries caused by the faulty system.

Regulators from the U.S. Environmental Protection Agency, the Department of Justice and the Florida Department of Environmental Protection descended on Miami-Dade in May with a 78-page consent decree, declaring the county had violated sections of the Clean Water Act, along with terms and conditions of its National Pollutant Discharge Elimination Systems permit.

The county’s aging sewage system has ruptured more than 65 times over the past two years, spilling over 47 million gallons of untreated human waste into waterways and streets from South Dade to the Broward County line. Those breaks were documented in letters sent to Miami-Dade by environmental regulators over the past two years. The letters also warned that the county could be on the hook for damages and restoration and penalties as high as $10,000 a day.

The EPA estimates there are up to a quarter-million line breaks around the country each year, as struggling cities continue to deal with sewage systems that in some cases are 100 years old.

Miami-Dade was last hit with a consent decree in 1996, eventually settling on a $2 million payment. Back then the problem was a lack of capacity to drain water overflows. Now, despite spending more than $2 billion in repairs, the problem is leaky and breaking pipes, as well as aging water treatment plants in need of new technology.

The county’s Central District Wastewater Plant on Virginia Key is desperately in need of repair, having failed four times between October and December 2011, when it sent 19 million gallons spilling from the facility.

Just last week the county had to close down sections of Bird Road from Southwest 37th to 57th avenues, well-populated neighborhoods that run from South Miami through Coral Gables. Water & Sewer spokeswoman Jennifer Messemer said the county was forced to build manholes so workers could gain access to faulty pipes under the roadway.

“The Bird Road pipes are in critical condition now,” said Renfrow.

Miami Herald staff writer Patricia Mazzei contributed to this report.