Properties from St Martin’s Street to Bewell Street were all affected; however water supplies were soon restored.
A spokesperson for Welsh Water said: “In order for our teams to carry out an essential emergency repair last night in Hereford city, a water main in the area was isolated for half an hour meaning that a small number of properties were without water.
“Had the isolation not been put in place, there was a risk of damage to a nearby property.
“Supplies were restored immediately following this and we apologise to any customers affected.”