Two people died and two more were missing in Hebei province, state broadcaster CCTV reported.
Overnight rain dumped a record 145 millimetres per hour on Fuping in the industrial city of Baoding.
China's Water Resources Ministry has issued flood warnings to 11 provinces and regions, including Beijing and neighbouring Hebei, for floods from small and midsize rivers and mountain torrents.
Floods and landslides affected many villages in the Miyun district of the capital, with the rural town of Fengjiayu the most severely impacted and electricity and communications cut in some villages, CCTV said.
More than 3000 people have been transferred out of the area, Beijing News Radio reported on Sunday.
Beijing issued a warning on Saturday for geological disasters, including landslides and mudslides, after intense rainfall unleashed, for a second time, a year's worth of rain on nearby Baoding.
Northern China has experienced record precipitation in recent years, exposing densely populated cities, including Beijing, to flood risks. Some scientists link the increased rainfall in China's usually arid north to global warming.
The storms are part of the broader pattern of extreme weather across China due to the East Asian monsoon, which has caused disruptions in the world's second-largest economy.
Baoding's Xizhuang station recorded 540mm over an eight-hour period, exceeding Baoding's average annual rainfall of about 500mm.
The deluge affected more than 46,000 people, forcing 4655 to evacuate, CCTV reported.
