A vehicle ended up on its roof in the Grand River in Woolwich Township.
First responders were called to the area of Buggy Lane, near the community of Winterbourne, shortly before 7 p.m. on Tuesday.
Police said when they arrived the driver was still inside the vehicle in the water.
A 31-year-old man was taken to hospital as a precaution and Waterloo Regional Police also said he was arrested for impaired driving.
A neighbour in the area brought out his tractor to assist police and firefighters.
The bridge, owned and maintained by members of the community, is designed for horse and buggy traffic and not for vehicular traffic, according to police.
The investigation is being continued at the hospital.
