The GTA has been placed under a flood watch after heavy rain drenched the area Friday morning.
The Toronto and Region Conservation Authority says the region got 20-40mm of rain in the overnight hours, with the precipitation continuing in the late morning.
Environment Canada says another system approaching the GTA today could dump another 20-25mm of rain. There is also a risk of thunderstorms.
The TRCA warns that there is potentials for water levels to spill over riverbanks.
The authority advises extreme caution around all bodies of water.