The Sewer Commissioners are hoping to make billing more fair.

But first, they need to untangle an incomplete and confusing billing schedule dating back to 1998.

Because the town’s sewer department doesn’t have access to water usage, which is controlled by the two independent fire districts, billing is based on Equivalent Dwelling Units (EDUs). That means that homes and businesses are billed based on the department’s best estimate of their usage as compared to a theoretical average single-family home. 

The commissioners hope to adjust those billing rates to more accurately reflect usage.

“Keep in mind, this is only a proposal,” said Chairman Jim Giberti.

One flaw in the current system is that the owner of a one-bedroom home and the owner of an eight-bedroom pay the same amount for sewer usage. The commissioners are considering changing that, and instead charging homeowners an additional .5 EDU for every bedroom over two. 

That calculation would be based on the records kept by the Assessor’s Office. The department is currently working on compiling that data, which will also allow the commission to calculate the actual average number of bedrooms in Wareham and Onset homes.

Businesses are also charged based on formulas using the EDU as a unit. For example, under the new proposal, a bed and breakfast would pay .5 EDU for each guest room in the building. Currently, bed and breakfasts are billed for .25 EDU per room.

“No matter what we do, it’s not going to be total equity,” said Guy Campinha, the director of water pollution control. “Somebody’s going to have an issue, but we’ll do our very best.”

For some businesses — including the hospital, nursing homes and supermarkets — the department will need to investigate further to come up with a fair bill.

“If you have an input and you think it should be less, it is what it is,” said Campinha. “But I caution the board: We have liabilities and responsibilities, and as we cut these things, let’s make sure we don’t cut our budget up.” 

The board also discussed giving service stations that use oil separators to clean water a discount to encourage those businesses to be environmentally mindful.