The notice has been lifted after changes were made to the treatment process, the network was flushed and samples were taken, the water company said.
The water supply issues were caused by a disinfection problem at Pembury Water Treatment Works, and while there was never evidence that the supply had become infected, it did not meet regulatory standards for drinking, SEW said.
Boiling the water made it safe to drink, as doing so disinfects it, killing any bacteria or microorganisms in the supply with the heat.
Mr Whitfield apologised, adding that customers had a “very difficult and frustrating time”.
“Before tap water leaves any of our water treatment works, it goes through extensive testing. If it is not up to strict regulatory standards, the water treatment works shuts down automatically. This is what happened on 29 and 30 November at our facility in Pembury.
“For reasons we are continuing to investigate, the natural make-up of the water we abstract from the wells and springs around Pembury changed suddenly.
“It is very unusual for this to happen. It meant the way in which the raw water needed to be treated had to change and we tested a variety of solutions, whilst consulting industry experts.”
The water supply director said the boil water notice was introduced to allow customers to carry out day-to-day tasks.
“The water was chemically safe and all water sampling to date has shown no bacteria has been detected in this area,” he added.
“We will now undertake a full review of what happened and how we responded. We will put actions in place to prevent a similar issue and make improvements to increase our resilience.”
Customers, including businesses, will be compensated, SEW added.
