The water company is investing £3m to replace 12km of pipes across the village, to help reduce the number of leaks and bursts in the area.
Work started this week and the project is expected to be finished by the end of April.
Three teams of engineers will work at the same time throughout this phase the project to get the job done as quickly as possible, with the first team concentrating on Station Road, close to Peel Street, before moving on to Mansfield Road, finishing near to Watson Avenue.
The second team will work in the Bailey Brook Drive area, finishing on Marshall Street, with team three starting the final phase of work in the Brampton Avenue area, finishing on Howitt Street.
Fire crews deployed to ‘large’ blaze in Mansfield – with people evacuated as flames spread to nearby properties
Letter: Unfair that disabled can no longer access water park
Creswell properties evacuated as fire crews tackle field blaze
Large fire in Kirkby may have been a 'deliberate or a careless act'
Man who doused victims with petrol in Mansfield locked up
To keep Severn Trent engineers and other road users safe, temporary traffic lights will be in place in various locations in the area.
Lisa Orme from Severn Trent said: “It’s fantastic that we’re now entering the final phase of this essential project.
“We’ve made some great progress and we’d like to thank everyone for their patience and understanding throughout this project.
“We’ve invested a large sum of money to ensure our customers in Langley Mill have a modern and reliable water network that will last for generations.
“We will do everything we can to get this work completed on time and return the area back to normal.”