Hundreds of homes in north and east Ipswich were left without water due to a burst main pipe.
Anglian Water confirmed engineers were dispatched to fix the issue, which was first identified on Saturday afternoon.
The supplier said the pipe should be repaired by 9pm.
According to the company's online tracker, the outage was affecting homes over an area covering half of the town.
Anglian Water said customers might experience low or no pressure at all.
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