The sewer rate in Wareham has remained the same for years, but that could change soon.

The town is waiting for the results of a study to determine whether it should keep the current system of charging sewer users a flat rate, or charge based on water usage.

The study, which is being conducted by Pocasset-based engineering and environmental consulting company Tinge & Bond, will examine the past five years. The study will not exceed $17,500, and is being paid for out of the Water Pollution Control Facility's budget for expenses.

In the meantime, the Selectmen on Tuesday decided to hold off on setting the sewer rate for the current year until they get the results of the study and until they get a number back from the state Department of Revenue on how much it costs to run the Water Pollution Control Facility.

"I think it's a question that does need to be answered," said Selectman Judy Whiteside after some discussion among the board. "We really do not have any idea when you get into the total cost of the system."

"You can set the rate again in January if you choose to," should the study determine that rates should rise, "which it probably will," Guy Campinha, Water Pollution Control Facility director, told the Selectmen.

Campinha also stressed that the town needs to set a rate that reflects the true cost of running the facility. In addition, the facility must look at sustaining itself over the long term, and the upkeep of pumping stations needs to be addressed.

Emergency repairs to the aging sewer system in Onset and Swifts Beach, where Campinha says the most incidents occur, cost approximately $120,000 per year. Pipes below the water table, as well as pipes that contain asbestos, add logistical issues to maintenance and repair.

Currently, the town charges $596 per property per year, and users are billed $298 twice a year at six-month intervals. The fee is based on how many EDUs -- or "equivalent dwelling units" -- are on a property. For example, a single-family home would be charged one EDU, while a two-unit duplex would be charged two EDUs.

Town Administrator Derek Sullivan said that resolving the sewer rate issue could give the town a boost in the eyes on the state Department of Revenue.

"It drives the Department of Revenue crazy that we keep the same rate every year," said Sullivan.