The main A371 near Bratton Seymour has now reopened after drainage improvements were completed a week ahead of schedule.
The scheme, which should help reduce the risk of future flooding by upgrading drains and gullies, was due to take four weeks and started on Monday 10 August.
Cllr David Fothergill, Somerset County Council’s Cabinet Member for Highways, said: “I know our highways team have really pulled out the stops to complete this work early and I’m delighted we’ve been able to reopen the road before the bank holiday weekend.
“Sometimes we cannot avoid causing some disruption to carry out improvements, but we really do try to keep this to a minimum and only ever close a road when it is absolutely necessary.
“This road is now safer and more resilient to bad weather. My thanks again for your patience.”