The bodies of all the killed have been retrieved, local officials said.
The accident took place at 9:40 am (local time) in a remote village in Suichang County in Lishui City.
Over 60 firefighters, police officers and rescuers were dispatched to the scene after the accident happened, state-run Xinhua news agency reported.
The vehicle was transporting three geologists on their way to conduct an official survey nearby and four local villagers.
The driver and one of the villagers managed to reach the shore and walked to report the incident.
Divers found all the five bodies later.
Road accidents are a serious problem in China.
According to World Health Organisation (WHO), more than 250,000 people are killed in road accidents in China.
The country's frequently overcrowded long-distance buses are prone to accidents, with individual incidents regularly causing dozens of deaths.
Road injuries are the third leading cause of premature death in China, ranking above any individual form of cancer, according to the Global Burden of Disease Study, a global research programme.
