South East Water has shut the road while it repairs part of a 17km-long pipe that runs from Bray to Swinley Forest.
Residents still have access along the road but other traffic is being diverted along Forest Road and Chavey Down Road.
The company aims to finish work by the end of August and will then continue repairs in Priory Road which will take a couple of days. Temporary traffic lights will be put in place while work is carried out.
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