Three bottled water stations – at Asda, Tesco and Sea Road – were due to re-open at 08:00 on Tuesday.
Southern Water said it had distributed more than a million litres of water to customers over the past four days – making it the biggest bottled water operations ever handled by the company.
Paul Mandry, the owner of the music venue The Crypt, said he had been forced to close, and called on Southern Water to invest more into solving the problems.
“I don’t really think they care about the small businesses in Hastings and the affect the floods and now the burst water main is going to have on the town,” he told Radio Sussex.
Over the weekend, East Sussex councillor Godfrey Daniel said: “The impact on the town will be drastic, a lot of people will lose a lot of money.
“These businesses are struggling as it is with the cost-of-living crisis.”
Southern Water apologised for the disruption the outage had caused, “especially over the bank holiday weekend”.
