BATH & North East Somerset Council is advising people plan their journeys from Monday July 24, when the B3116 Wellsway in Keynsham closes for up to 12 weeks to allow a new relief sewer to be built.
A diversion route will be in place during the closure, which extends between the entrance to Rockhill Estate to its junction with Bath Road.
The council has asked Wessex Water to time the works to coincide with the start of the school summer holidays to minimise disruption to traffic.
Wessex Water is building the new sewer to tackle long-standing issues with flooding in the area.
Alex Aulds, project manager for Wessex Water, said: “We have met with councils in both Keynsham and Saltford to better understand the impact this road closure will have and ensure the appropriate measures are in place to direct traffic on to the diversion route.
“We have also written to residents, schools and businesses locally to make them aware of the project and are working closely with Keynsham Cricket Club, near to the site of the project, to reduce the impact as much as possible.’’