Attempts will be made to repair the fault that has seen untreated sewage enter the sea at a local beauty spot.
Normally, the sewage outfall below Fort George takes waste out to sea, beyond Soldier's Bay, where it is dispersed by the currents and broken down.
But, for some time, a fault has seen effluent discharged into Soldier's Bay.
As it is sheltered from most winds, some of it is staying close to shore.
Although fenced off and inaccessible by foot, Soldier's Bay is used by mooring boats, fishermen have pots there and long distance swimmers cross the bay as they head southwards from St Peter Port.
The pollution was discovered by the BBC locally, who were filming with a drone and they alerted Guernsey Water.
The company says it informed the Office of Environmental Health and Pollution Regulation and it is keeping them up to date as they monitor water quality in the island.
Guernsey Water carried a detailed technical inspection, using a robot, drones and chemical dyes, to find a fault in the inspection chamber, which is only accessible at low tide.
It says an effort will be made using upcoming spring tides to fix the issue.
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