According to some local politicians, up to 80mm of rain fell in fewer than two hours.
ADVERTISEMENTRome's mayor has come under fire after flooding in the Italian capital.
Fire crews carried out 150 interventions across the city on Tuesday, including rescuing people trapped in cars.
According to some local politicians, up to 80mm of rain fell in fewer than two hours.
In the Corso Francia area of the city, 40 children and six teachers were evacuated from a flooded nursery school, authorities said. Local media reported that the children and adults were taken safely to a nearby hotel for shelter.
A number of restaurant owners reported that their terraces had been affected by the floodwater and several vehicles could be seen submerged up to their headlights. Many of the city's transport links were also affected. A disabled man was also rescued from a flooded car that had broken down near the San Paolo station, the carabinieri said.
Local politicians pointed the finger at mayor Virginia Raggi and the Five Star Movement (M5S), claiming the flooding should not have caused as many problems as it did.
"The mayor has to explain what is happening in Rome," tweeted Carlo Calenda, leader of the Azione party and a mayoral candidate.
"If we continue not to keep the manholes clean, we risk having to borrow the Mose from Venice," said centre-left candidate Roberto Gualtieri, referring to the northeast city's flood defence system.
Luciano Nobili, deputy of Italia Viva, also said that it was "unacceptable" that the city had been "completely flooded" after the rainfall and that children had to be evacuated from a nursery school.
"Every time, a simple storm in Rome becomes a cloudburst, enough Raggi, enough," Nobili tweeted.
A local infrastructure councillor has defended the city's mayor and administration, describing the thunderstorm as "extraordinary".
"It was an exceptional event, a 'water bomb' that hit the northern area of Rome," said councillor Linda Meleo on Facebook, adding that the city would soon launch two maintenance contracts worth €5 million to help with the clean-up effort.