I used to live near Yalding, it flooded most years and I got used to it, we bought a high 4-wheel drive to cope. My daughter moved back to Kent, to Maidstone, her house flooded a couple of weeks ago and she has just had a new front door with extra strong seals installed and new fencing around her garden, as it all came down. The rainfall isn't high in Kent, it's the solid clay that is the problem I think, all the water just washes over it. I lived in various parts of it for 45 years and flooding was a problem in most areas, unless you lived high up on the Downs. I lived in Chainhurst for a while and we were marooned for a week one new year, all roads were impassable.
A farmer friend told me that the problem is people filling in their drainage ditches to gain more garden/field space. All you need is one person in the chain filling in the ditches, or not bothering to clear them, and everyone gets flooded. I have watched the same thing happening here in Suffolk, we live at the edge of a watermeadow. A neighbour's garden is edged by a ditch and he has spent years disposing of his horse bedding into it, much to my horror. The estate owners adjoining us have spent the past week digging out the ditches and dumping it all right back on his land. I was very relieved.