Barwon Water is investigating a number of repair options for a damaged sewer pipe beneath the Anglesea River.
Specialist divers placed a stainless steel sleeve around the damaged section late yesterday, but the repair was unsuccessful.
The sleeve was tested using recycled water, a small amount of which escaped.
A warning sign was re-instated as a precaution and further water quality tests conducted at seven different monitoring sites. All results were below the acceptable safe level of 1,000 organisms per 100 millilitres.
Further tests will be taken.
A leak in the main, which was carrying about 85 per cent Class C recycled water from Aireys Inlet and 15 per cent sewage from west Anglesea, was discovered last week.
It was shutdown immediately and continues to remain offline.
Barwon Water's General Manager Water Systems Carl Bicknell said the repair was proving difficult because the pipe was submerged beneath water with extremely poor visibility.
The repair options included inserting a flexible sleeve inside the pipe or constructing a new pipe crossing.
"This is a very challenging task, particularly because of the ground conditions which have changed dramatically since the pipe was constructed," Mr Bicknell said.
"We are obtaining the very best advice before proceeding," he said.
A decision is expected early next week.
Meantime, sewage from west Anglesea will continue to be trucked to the Anglesea water reclamation plant while the recycled water will be stored in purpose-built lagoons at Aireys Inlet.
Mr Bicknell again stressed there was no health risk to residents.
He said water monitoring would continue while the options were considered.
Barwon Water continues to liaise with the EPA, Corangamite CMA, Department of Sustainability and Environment and Surf Coast Shire.
The community will continue to be updated through the media and on Barwon Water's website.