Bad weather hit a large swath of the Atlantic coast of this southeastern Brazilian state, particularly the resort town of Paraty, where a mother and five of her children died in a landslide, authorities said.
Two other people died, respectively in Mesquita and Angra dos Reis, and 13 are also missing, according to Marcelo Freixo, congressional representative for the state of Rio de Janeiro.
In Angra, a four-year-old girl was buried by a landslide.
In Mesquita, a 38-year-old man died of electrocution while trying to help another person escape flooding, according to media reports.
These heavy rains fell on the state of Rio de Janeiro for two days.
Friday evening, they turned the streets of several cities into torrents and triggered landslides, a frequent phenomenon during the rainy season, especially in poor hillside neighborhoods.
Angra thus received 655 mm of rain in 48 hours, "
levels never recorded before
", according to the municipal authorities.
The bad weather comes six weeks after flash floods and landslides killed 233 people in Petrópolis, also in the state of Rio de Janeiro.