The incident director leading the response to a parasite outbreak in Devon said teams were working around the clock to “urgently fix the problem”.
South West Water (SWW) said 2,500 properties across Brixham were still being affected after cryptosporidium was detected on 14 May.
The water firm continues to advise affected residents in Hillhead, upper parts of Brixham and Kingswear to continue to boil their drinking water.
David Hill said he was aware of the “frustrating” situation especially over the bank holiday weekend.
The UK Health Security Agency said a further 20 confirmed cases of cryptosporidiosis have been confirmed in Brixham, taking the total to 77.
Mr Hill said “good progress” was being made but the boil water notice would only be lifted when “public health officials are fully confident it is safe.”
Mr Hill said teams have been rigorously cleaning, testing and installing filters.
“This meticulous process does take time, and I am sorry for that, but public safety must be our first and foremost priority,” he said.
The incident director said the company was continuing to deliver bottled water daily to properties across the boil water notice area.
“I want to thank local people for their patience while we work to resolve this situation,” he said.
