Delaware County on Thursday sued to block the $276.5 million sale of the county’s sprawling public sewer system to Aqua Pennsylvania, the company’s largest privatization of a public water or wastewater system in Pennsylvania.

The county council, which Democrats took over following November’s election after more than a century of Republican control, said last year’s sale agreement between the Delaware County Regional Water Quality Control Authority (DELCORA) and Aqua was a hasty no-bid deal to a politically connected company. The council said the sale was designed to prevent an important patronage stronghold from falling into Democratic hands when political control of the county changed.