China has been battered by unprecedented rains in recent months, extreme weather that experts say is increasingly common due to global warming.
In Hubei, torrential rains caused power cuts and landslides, destroying hundreds of homes and forcing the evacuation of nearly 6,000 people, the province's Emergency Management Bureau said, as reservoirs reach dangerous levels.
"Twenty-one people were killed and four others are missing as heavy rain lashed townships from Wednesday," state broadcaster Xinhua reported Friday.
Footage showed families wading in water that had risen to almost hip level and carrying essentials in plastic bags in Yicheng, which saw a record 480 millimetres (around 19 inches) of rain on Thursday. Rescuers carried people to safety on bulldozers.
"Yesterday the water levels rose to about two to three metres. My neighbour's house was completely destroyed," a resident from one of the worst affected areas in the city of Suizhou told local media.
"We haven't seen so much rain in 20 or 30 years."
Hundreds of firefighters and thousands of police and military have been dispatched to the worst affected areas, China's Ministry of Emergency Management said.
Around 100,000 people were evacuated in the southwestern province of Sichuan last weekend as heavy rains caused several landslides.
More than 300 people were killed in central China's Henan province last month after record downpours dumped a year's worth of rain on a city in three days.
China's Meteorological Administration warned that heavy rainfall was likely to continue until next week, with regions along the Yangtze River, including Shanghai, vulnerable to flooding.
