Thousands of homes and businesses in North Ayrshire and Inverclyde were left without water for hours on Wednesday and Thursday due to a closed valve.
At around 11am on Wednesday, people in Inverkip, Wemyss Bay and Skelmorlie were left without access to fresh running water without prior warning.
Scottish Water explained on Thursday morning the outage had been caused by a closed valve in their network.
The firm said teams had managed to resolve the issue and restore customer supplies after working through the night, and were now recharging the water main to prevent further issues.
One customer said on Wednesday they had contacted Scottish Water multiple times for information, but had been left hanging while the outage was ongoing – including on social media.
They said: “They have also left the vulnerable and those with medical needs without updates or water supplies even though they are on their ‘priority’ list. It’s terrible.
“They have not delivered bottled water either. I thought you should know as people are very angry. Families can’t even wash their hands or flush the loo. We have no idea when it will be fixed.”
Another told STV News their local pub was closed for the evening as a result, causing them to miss the last FIFA World Cup match ahead of the final on Sunday.
A statement by Scottish Water read: “We apologise to all affected customers for any inconvenience or disruption caused.
“We are working hard to restore water supplies for all customers as soon as possible this morning.
“While the water main recharges, you may experience no water supply, low/intermittent pressure or discoloured water.”
It added: “We would like to thank our customers for their continued patience while we work to resolve the issues.”