Waterworks will begin in Barnsley at the start of next week.
The work is part of a £7 million project to improve water pipes in the town, being carried out by Yorkshire Water.
A large water main alongside Barnsley Road, between the junction with Cone Lane and the Lord Nelson public house in Hoylandswaine will be cleaned, taking about eight weeks.
Temporary traffic lights will be used at different locations on the stretch of road, so the main can be cleaned safely.
Mike Tunnicliffe, project manager, said: “This will enable us to ensure the highest- quality water supply for our customers.”