The flash flood swept through parts of Zhongshan village in Mabian county in the early hours on Sunday, according to the provincial disaster relief office.
Roads and telecommunications facilities were also damaged, the office said. The search for the missing continues.
Across the country, 128 people have been killed and 24 are missing in this year's flooding, according to the State Flood Control and Drought Relief Headquarters.
China Central Meteorological Station is warning of possible floods and landslides in western China which is likely to receive heavy rain over the next two days.
In northwestern Ningxia region, landslides would be possible after a rainstorm on Friday hit Xiji county, threatening the safety of 234 villagers.
The Ningxia meteorological station issued red warnings of rainstorms, alerting residents to the danger of possible floods in southern mountainous areas of the region.