Manx Utilities says the old Castletown Road will close for more than two weeks next month.
It says the White Hoe Wastewater Pumping Station needs essential refurbishment work, including replacing manhole covers.
As a result, the road will close from Monday, March 9 until Wednesday, March 25.
Motorists will be diverted to the White Hoe Industrial Estate via Kewaigue Hill Road, and via Quarterbridge into Douglas.
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