Oxford’s Radcliffe Meteorological Station reported the city saw 62% more rainfall than usual in January, while 88% of the typical monthly amount has already fallen in the first 10 days of February.
Mansbridge said groundwater was now adding to the problems.
A groundwater alert remains in place for Lambourn Valley, and he warned of “lots more impact over the next month or so”.
He reminded residents that flood alerts mean flooding is possible, while warnings mean it is expected.
People in at‑risk areas should move valuables upstairs, relocate cars to higher ground and ensure pets are safe.
“My advice is not to drive or walk through floodwater because it is often murky, you can’t see what is underneath – like a manhole cover can pop up – and there is a danger to life,” he added.