Tens of thousands of people in East Sussex and Kent are starting the working week without water following a weekend of disruption, with the council in Kent declaring a major incident.
South East Water (SEW) said a number of issues were to blame, including Storm Goretti and a power cut at its pumping plant.
It said 14 postcodes were still affected around the East Grinstead, Frant and Tunbridge Wells areas.
Collection points for bottled water have been set up and some customers have been told their supply may not return until Tuesday.