SPRINGFIELD TWP, Mercer County — Three municipalities in southeastern Mercer County have approved a tax increment financing (TIF) district that officials hope will spur another round of major economic investment.

This week Springfield Township supervisors approved the district, finalizing a proposal that will fund water and wastewater upgrades along the Route 208 corridor. The TIF proposal, which already has been approved by the Grove City School District, also needs approval from the Mercer County Commissioners.

The area is home to the Grove City Premium Outlets, as well as a cadre of restaurants, gas stations and hotels.

It has been a hotbed of economic activity for years. The outlets alone reportedly draw about 6 million visitors each year, said Randy Seitz, the executive director of Penn-Northwest Development Corp., Mercer County’s lead economic development agency.

“We’ve quickly grown to the point where, even though there’s strong interest ... we just don’t have enough capacity,” Seitz said.

A TIF uses incremental increases in property sales or other tax revenues in its boundaries to finance infrastructure improvements.

The TIF would raise nearly $13.5 million over 20 years. About $3 million of that is the township’s share of a $10 million project that will upgrade the capacity of a sewage treatment plant owned by Grove City, said Rick Dillaman, chairman of the Springfield Township supervisors.

The borough’s treatment plant has processed all of the mall’s sewage since the outlets were built in 1993.

The facility also serves customers in Pine and Liberty townships.

Dillaman said that design engineering on the plant upgrades will begin soon and should take six to eight months, with the project expected to start construction in 2017. The township also plans to do municipal water service upgrades to the area, Dillaman said.

Seitz said the sewage upgrades are “definitely needed right now” to allow for more development and reinvigorate interest from companies willing to invest in property around the mall.

He said PennNorthwest has talked with a client that has plans to build two hotels and two restaurants near the mall, but those projects wouldn’t be finalized until the sewage upgrades were in place.

Seitz said the 1,200 acres in the TIF zone offer a variety of development opportunities, including parcels at the far ends for light industry, such as machine shops, fabrication businesses and warehouse distribution companies.

Parcels closer to the mall will be marketed to national and international retailers, Seitz said.

“We’ll be talking to all the ‘big box’ retailers we possibly can,” he said.