Maryville voters head to the polls tomorrow to consider approval of a bond for waste water system improvements.

The improvements to the sewer system are required under the Clean Water Act.

The $13.75 million bond would build a new mechanical waste water treatment plant to replace the city’s lagoon system. Combined water and sewer rates could increase 25-30 percent.

If it fails, the city will have to go another route to find funding to meet the Clean Water Act requirements to avoid penalties.

Construction would begin in December of 2013.