It will cost Largo about $73 million to overhaul its sewer system.
That's the latest estimate, after an extensive study that evaluated potential costs to curb the amount of sewage that overflows from the system and to comply with environmental regulations.
Largo doesn't know exactly yet how much the upgrades will affect sewer rates.
But one thing is for sure:
"Rates will go up," said Kim Adams, the city's finance director. "We cannot absorb $70 million in our budget."
The hefty price tag for the overhaul is actually good news. Largo thought it would cost about $100 million to satisfy an agreement with the Florida Department of Environmental Protection and meet other regulatory requirements.
In 2006, the city entered into an agreement with the DEP for violations of the federal Clean Water Act and the city's permit to operate its Wastewater Reclamation Facility. Largo agreed to significantly reduce the overflows and improve the disinfection system at the treatment facility by 2016.
If the city turned down the agreement, the DEP could have levied steeper fines or taken Largo to court to force it to improve the system in a shorter time period.
Such agreements are quite common, according to DEP spokesman Doug Tobin. The DEP is continually working with governments, businesses and other entities to bring them into compliance with regulations, he said.
Overflowing sewage can contaminate waterways or back up into homes.
Various parts of Largo's system have the potential to overflow. But a portion of Donegan Road is most prone to discharges in a big storm.
The overflows have a variety of causes. Pipes can break. Grease or dirt can clog the lines. They can also be caused by cracks or gaps in some of the lines, said Irvin Kety, environmental services director for the city.
When there's a heavy rain, water can leach into pipes. If the line fills up, the water has to go somewhere. Excess water "will literally pop the manhole up and sewage will start going on the street," Kety said.
The city also plans reclamation facility upgrades to reduce the amount of nutrients that it discharges and change the way it disinfects treated wastewater.
The city plans to borrow money to fund the overhaul and is in the process of prioritizing various capital projects to see how it will impact sewer rates.
The city has already projected a 20 percent rate increase for next fiscal year. By April, city officials expect to have a better grasp on how much and when rates may increase, Adams said.