The main road just north of the Forester's pub is divided by cones and is down to two lanes for the coming eight weeks.
Guernsey Water is beginning work to refurbish an ageing pumping station at a cost of £300,000.
The company describes it as 'a major piece of work' and an 'investment into the island's critical water infrastructure.'
From today (18 March), cones are marking out a two lane system that allows workers to access the station on the seaward side.
Pipes under the road will be replaced and the control panel moved to the landward side.
At times, traffic lights will need to be used.
Carl Falla from Guernsey Water is overseeing the work:
"The investment means we can continue to ensure wastewater is safely returned to sea for decades.
This station is a small yet vital piece of the island’s critical infrastructure.
I want to thank everyone in advance for their patience as we undertake this work."
Once work on the pumping station is finished, the road will be resurfaced.
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