Muddy water gushed through streets in a village in Dayuan township, pouring into houses and turning over cars, pictures published by the Beijing Youth Daily showed.
China typically sees heavy rain in late July, but storms have become more intense and unpredictable in recent years.
Torrential rain also submerged parts of China’s northeast on Saturday, damaging dozens of houses and ruining crops in the region known as the nation’s breadbasket.
Almost 5,600 people were evacuated by authorities in Liaoning province, reported state broadcaster CCTV, after several cities received more than 100 millimetres of rain.
One district of provincial capital Dalian received 93 millimetres of rain in an hour.
Rescue workers were seen wading through water up to their knees with inflatable dinghies, pictures published by CCTV showed.
About 54 hectares of crops were damaged in the area around Jinzhou and the coastal city of Huludao.
Parts of the northeast had been hit by drought in May and June but recent rain has alleviated the situation, the agriculture ministry said on Friday.
It added that there were still risks to local crops – mainly corn and soybeans – with this year’s El Nino weather pattern likely to bring more extreme weather.
More heavy rain was expected on Sunday across much of the country, with rain storms and strong wind in parts of the northeast and southern Jiangxi and Fujian provinces.