Twelve thousand properties are still without water in parts of Bedfordshire.
Anglian Water said a damaged valve caused the initial problem in the Leighton Buzzard, Heath and Reach, and Toddington areas which began yesterday evening.
Around half the homes were reconnected at lunchtime on Saturday (14 December) but a spokesman said 12,000 remained without a supply because of a suspected airlock. Problems have ranged from low pressure to no water at all.
Engineers have fixed the valve and are now trying to find the airlock and deal with that.
Water was re-directed from a reservoir to begin with but quickly ran out. Anglian Water said it had given bottled water to the most vulnerable people affected, including the elderly and mothers with young children.