Drivers are being warned of the temporary road closure on the A81 between Balfron Station and the Ballat Crossroads from 18 September for around 14 weeks, whilst the repairs are carried out.
A diversion will be in place from the A81/B834 roundabout which will direct drivers via the A811 Stirling Road.
Scott Fraser, Scottish Water’s corporate affairs regional manager, said: “This work is essential to repair the bridge near Balfron Station which was struck by a lorry last September.
“We have liaised closely with Stirling Council while we carry out this important work and we will do all we can to complete it as quickly as possible.
“We apologise for any inconvenience and thank affected residents, road users and the community for their patience and understanding.”