MIDDLETOWN — Two weeks into the start of a townwide sewer-system inspection program, officials say nearly 400 houses may have illegal sewer connections.

Town Administrator Gerald Kempen said many of those residences have yard drains or roof leaders running into the ground, and officials need to determine whether they are carrying rainwater into the town’s sanitary sewer system instead of its storm drains, which places an added strain on the Wave Avenue pump station.

That water, a corroded Memorial Boulevard force main, a pump station badly in need of upgrades, and cracked manhole covers and sewer lines have all contributed to three sewage overflows in a little over a year. Officials hope to have any illegal tie-ins corrected in time for the start of next year’s beach season in May.

Over 1,500 houses have been inspected since engineers set out on Oct. 8 to visit Middletown’s 4,500 sewer customers. Engineers have attempted an additional 2,000 inspections, but couldn’t enter the properties.

“They’ve hit the ground running,” Kempen said of Crew Two, Jose Casali Engineering Inc., and Garofalo & Associates, who were contracted to conduct the inspections. The program will cost $200,000, and is being paid for through the town’s sewer fund.

The town is also considering hiring a fourth company, and hopes to complete the inspections by the end of the year.

“They’ve made tremendous progress during the first two weeks, so I think we have an excellent chance of doing this,” Kempen said.

Residents with illegal tie-ins are asked to reroute the pipes from their roofs or sump pumps onto their lawns or into the town’s storm-drain system, and to fill the area with cement. Kempen says the town won’t finance repairs but is available to help residents with the process. Property owners who don’t comply with the inspections could be taken to Municipal Court and face fines.

Kempen stressed that the town was not blaming residents with illegal sewer connections, which are present in many houses that predate the town’s wastewater-treatment plant. Decades ago, both sewage and rainwater would flow directly into the ocean through the same pipes. After the plant was built, those pipes were rerouted to flow into the treatment plant, he said.

“The majority of residents don’t even know where their pipes go,” Kempen said.

Kempen said the corrections would benefit both the town and its sewer ratepayers. Reducing the sewer system’s water intake will also prevent future overflows and fines, he said, citing a similar program conducted in South Portland, Maine, a few years ago. Officials removed 58 million gallons of clean water that previously flowed into that city’s sewer system every year, he said.

“If we can accomplish something similar, we can bring a direct benefit to our ratepayers,” Kempen said.