Manx Utilities says motorists face six months of misery as it improves the capital's sewage system.
Work on a 23-week project on the Old Castletown Road will start on Thursday.
Kewaigue's pumping station will be replaced, and work will take place on the Old Castletown Road and Heron & Brearley brewery site.
There'll be a number of road closures and traffic restrictions between Thursday, April 3 and Wednesday, April 16.
DOI considering options to develop farm site
Government has over 60 PR and marketing staff
Uni students to get more government support
Tynwald votes in favour of lower minimum wage rise
Noel Edmonds launches exclusive Isle of Man wines
Sailings cancelled in today's bad weather
Yellow weather warning today
No body camera plans for social services