High Road in Letterkenny will be closed for six weeks beginning January 9, 2023.
Diversions via New Line Road/Glencar Road and Market Square/Main Street will be in place.
De Valera Road, Main Street and Pearse Road will also be used for diversions.
Access to the upper part of High Road can be achieved via Church Lane/Ard O’Donnell/New Line Road.
Donegal County Council said this work has been planned by Irish Water.
“They should be your first point of contact if any issues arise during the on-going of works,” a spokesperson said.