Anglian Water said a 6 ins (15cm) main had burst at about 12:45 GMT on Woodbridge Road East, near the Lattice Barn pub.
Its engineers were able to stop the leak onto the road by about 14:30 GMT.
Police had to direct traffic around the damaged road, while the water company said it would take two days to fully fix.
Antony Innes, from Anglian Water, said: "Unfortunately, the leak has caused damage to the road surface which will need fixing before the road can be reopened.
"We expect to have things back to normal by Wednesday morning, but will be doing all we can to put things right as soon as possible."
Mr Innes said the road would have to be closed in both directions from 18:00 GMT until the surface was repaired.
He said 30 houses had had their water restored and the rest should be back on later on Monday.
A burst water pipe has cracked open a main road in Ipswich and left 50 homes without supplies.