WATERVILLE — Motorists can expect closures on parts of Pleasant Street starting Tuesday as the Kennebec Water District ramps up a $3.7 million project to replace the water main on that street and some streets off Pleasant.

Preliminary work started last week on the project, which will replace old water mains on not only Pleasant Street, but also on Pleasant Place, Pleasant Court and Center Street.

On Tuesday, for just one day, Pleasant Street will be closed to traffic from North Street to Gilman Street and local traffic will be able to access that portion of the street from Gilman Street only, according to KWD officials. Traffic will be detoured to Gilman and North streets via Middle Street.

Starting Wednesday, Pleasant Street from Main to North streets will be closed to all traffic, which will be detoured via North Street. Access to Kennebec Savings Bank and Mobile Mart will be possible  from their North Street driveways.

That road closure is expected to continue for three weeks. Those with questions about the project are asked to contact KWD project engineer Max Kenney at 207-872-2763.

The water mains on and around Pleasant Street are being replaced because they are old and undersized for the demand, according to Kenney. He told city councilors last month that some of the 2- and 6-inch cast iron mains to be replaced are 100 or more years old, and those on Pleasant and Center streets were installed in 1903. The replacement is expected to improve water quality to allow more water to pass from KWD’s Western Avenue pump station to the Main Street corridor, according to Kenney.

The contractor for the project is Nitram Excavation & General Contractor Inc. of Benton. The Maine Drinking Water Program, in coordination with a state revolving loan fund, is the funding partner. The project will be done in three phases, with the first phase to include replacing the main on Pleasant Street, between North and Main streets. The second phase, estimated to start April 24, will be the largest phase and will include work on Pleasant Street, from North Street to Park Street and including Pleasant Court, Pleasant Place and Center Street. The third phase, estimated to start June 17, will include Pleasant Street, from Park Street to Western Avenue. That phase includes the area in front of the Albert S. Hall School, so the work will be done in the summer when school is out.

KWD is the municipal drinking water utility for Waterville, Winslow, Fairfield, Benton and Vassalboro. KWD also sells water wholesale to Maine Water Co., which provides water for Oakland.