Scottish Water was carrying out the works at Philiphaugh on the outskirts of Selkirk whilst laying new pipes between Howden and Yarrowford.
A Scottish Borders Council's archaeologist said:
"It is an exciting discovery. It is not every day that medieval villages are found - most of them are known, this one was completely unknown."
More top news
Holyrood's Finance Secretary has insisted most Scots will pay less income tax next year, despite increasing charges for higher earners.
The 13-month-old collapsed at home with injuries a pathologist suspected were caused by a sexual abuse, Kendal Coroner's Court was told.
Conservative John Stevenson defied his party's whip to vote in both the ayes and noes lobby over Brexit legislation.