More rain is on the way, which may lead to flooding in some areas.
The Lower Thames Conservation Authority says the water levels are expected to continue rising, heading into next week.
Water Management Supervisor Jason Wintermute says the more immediate rise in levels will be seen as a result of the predicted 30 mm of rain Wednesday and Thursday.
"This time of the year when there aren't too many crops on the field and that kind of stuff, the rain doesn't really get trapped and so it can run off into the local ditches and creeks fairly easily," says Wintermute.
Although the rain is expected to stop in Chatham-Kent during the weekend, the water levels could still rise depending on how much rain hits the London area.
"The Thames watershed kind of collects in London and then comes down the river," says Wintermute. "That takes a while so we'll get our immediate response here but then the water that comes down to us from London takes two or three days."
He adds the water levels are expected to be higher than the levels seen during the Christmas holiday.
Residents are being asked to be careful around the Thames River. Wintermute says the combination of slippery banks, unstable ice, and fast, cold moving water can be dangerous.