BANGOR, Maine — City councilors have remained committed to holding the tax rate flat during budget discussions so far, but they can’t seem to stop a number of fees from inching upward.

The latest fee increase, approved at a council meeting on Monday, is a 5 percent sewer rate hike that will go into effect beginning July 1. For the average residential consumer, that means an extra $1.67 per month, or about $20 annually.

Brad Moore, Bangor’s wastewater superintendent, told councilors Monday that more revenue is needed to complete upcoming projects, many of which are either state or federally mandated. Among those projects are a capacity management study, a sewer mapping project and other long-term planning initiatives.

Failure to complete specified projects, Moore said, could result in regulatory action as well as increased scrutiny over development projects, both of which would be more expensive for the city in the long run.

All told, the city is expected to increase the annual budget for the wastewater department by about $360,000, none of which will go toward staff salaries or benefits. Over the next 10-15 years, Moore said Bangor could expect to spend tens of millions of dollars to upgrade its sewer systems.

Councilors were not thrilled to approve the rate increase on Monday, but they also understood that they didn’t have much of a choice.

Bangor’s last sewer rate increase came in 2006, a jump of 7.5 percent, and was made largely to offset a big rise in electricity rates.

The sewer rate is not the only fee that will increase for Bangor residents during the next year. Earlier this year, the Bangor Water District announced a rate increase of 11 percent to cover an additional $560,000 in annual expenses.

As with Bangor’s sewer system, the reason behind the water rate hike was aging infrastructure. Many pipes and tanks that hold and supply water to homes and businesses in Bangor have aged and maintenance is required.

For the average user in Bangor, the planned rate adjustment translates to an increase of about 6 cents per day, or about $5.75 per quarter.

All water rate increase requests must be approved by the Maine Public Utilities Commission, which provides independent oversight but rarely goes against a district recommendation. The PUC has not yet ruled on Bangor’s request.

The Bangor Water District has increased its rate every other year since 2005. The last increase of 15 percent came in 2009.

Councilors also are discussing changes to the city’s recycling and trash removal programs, which could involve adding a fee for trash bags, but no final decisions have been made.