The 200 and 300 blocks of Nebraska Street in Ottawa are closed to all through traffic and parking.
Contractors for Ottawa are installing a new water main in those blocks.
The project is expected to be completed within two weeks. During that time, local traffic will be allowed and the area is expected to be open at night and the weekend.
The city asks drivers to use caution and to be aware of the presence of workers and construction equipment when traveling in the area.