DRIVERS face delays as work to repair a collapsed sewer under New Street, Henley, began today.
The road will remain shut for up to 18 days while 80m of broken pipe is replaced to prevent flooding in the town centre.
Diversions and signage will be in place while the work is carried out.
The broken sewer was discovered in March after residents experienced sewer flooding.
Repairs were carried out in April to protect homes and businesses but the full work was delayed until after Henley Royal Regatta.
Nigel Emes, contract performance manager for Thames Water, said: ?The sewer is in poor condition and, although it is working, we need to replace the broken pipe before it gets worse.
?Having taken a break to allow traffic to flow through the town during the regatta, we are returning to complete this work.
?We?re sorry for any inconvenience this may cause to road-users and residents. We are working closely with the local authority to minimise any disruption.?
The company says its engineers are working from 8am to 8pm on weekdays and 8am to 7pm on Saturdays.
The alternative route is via King?s Road, Market Place, Gravel Hill, Paradise Road, Deanfield Avenue, Greys Road, Duke Street and Hart Street.
Joan Bland, who owns Asquiths teddy bear shop in New Street, fears her deliveries will be disrupted.
She said: ?Drivers are parking in the loading bays in Bell Street so businesses can?t receive any deliveries.
?I am waiting a delivery from Germany but I don?t know where the lorry is going to park ? it really is a problem.?
Mrs Bland, a town councillor, said that traffic congestion was ?inevitable? but it did have its upside. ?It is wonderful not having cars in New Street,? she said.