North Road, Newfields and the A1 Meadow House roundabout were among the worst affected areas.
Police have been restricting traffic coming into the town from the north.
It has been causing problems for Perryman’s bus services which were unable to serve Newfields due to flooding at the north end of the estate.
There have also been problems on the A1 at Beal and on minor roads across north Northumberland and the Scottish Borders.
There was over 20mm of rain recorded at the Letham Shank weather station, bringing the January total to 123.1mm - the long-term average is 53mm.