Environment Canada has issued several weather warnings for the region, including a severe thunderstorm warning for Peel Region and a special weather statement for Toronto and York Region.
In the Peel region, a storm over Brampton and the southern Caledon region was “almost stationary”, with many areas receiving around 100mm of rain.
Environment Canada said rainfall totals in excess of 120 millimeters are possible in those areas, which already received significant rainfall from a storm on Saturday.
A CP24 viewer sent video of a person kayaking in a flooded road in the area of ​​Hurontario Street and Highway 401. Another Brampton resident said Sunday’s downpour flooded his basement.
Prince Sharma, who lives in Hardgate Crescent, said water was constantly coming out of the city drain, filling the basement.
“There was nothing we could do,” Sharma said.  “We just tried to empty everything we could at the time. Try not to go in the water because it can be dangerous.”
Credit Valley Conservation (CVC) said the Credit River catchment had already received 10 to 35mm of rain before Sunday afternoon’s storm.
“While flooding of the Credit River and its major tributaries is not expected, there is a potential for localized flash flooding and pooling of water on roads and in floodplain and low-lying urban areas,” CVC said in its flood outlook.  which will be valid until August 22 or until further notice.
The severe thunderstorm warning for the Peel region ended around 9pm
Toronto was also under a special weather statement due to the storms.  Environment Canada said the northern part of the city will see the heaviest rainfall, adding that the area could receive 20 to 40 millimeters of rain.
The warning was lifted shortly before 9:30 p.m.  It will be mostly cloudy for the rest of the evening in Toronto with a 60 percent chance of showers.
Earlier this afternoon, the Toronto and District Conservation Authority advised of storms moving through the GTA that could drop up to 50mm of rain by the end of Sunday.
The group said watersheds in the greater Toronto area have already seen between 5 and 20 millimeters of rain in the past 24 hours.  About 53 millimeters of rain has also been recorded in the northern Etobicoke Creek watershed.
As a result of the downpour, TRCA advised that rivers within the GTA may experience higher flows and water levels.
“The combination of slippery and unstable banks and rising water levels could create dangerous conditions near rivers or other bodies of water,” it said in a statement.
People are advised to avoid all recreational activities in or around bodies of water at this time, including Lake Ontario.
Parents and guardians are asked to keep children and pets away from the riverbanks as they may have become slippery or unstable due to overnight rainfall.
A water safety statement for catchment conditions is in effect until Tuesday, August 23.
Clouds and humidity will continue for the next two days in Toronto.  According to Environment Canada, there is a 70 per cent chance of showers and a chance of a thunderstorm on Monday with a high of 24C.
For Tuesday, it will be cloudy with a 30 percent chance of showers and a high of 26 C. Sunshine is expected to return on Wednesday.