Public works crews and police officers responded to the water main break at around 3:15 a.m. Sunday morning, in front of the Tides Inn and Suites, 1807 Water Street.
The break has closed Highway 20 between Washington Street and the Port Townsend ferry terminal. Crews with the state Department of Transportation are setting up a detour route on city streets.
Public Works personnel say water pressure was not lost in the transmission lines, so no water boil advisory is necessary.
This is a developing news story. More information will be posted as it becomes available.