responsibility for neighbour's flooding?

[Amilcar]

Our adjoining neighbour may try arguing that flooding at his house is due to water from higher surrounding land being diverted by our building extension's foundations to flow under the party wall. We believe that the natural flow of water misses us, being higher, and would flow into his unwaterproofed old house, anyway. But it is legally advantageous for him to claim that our extension is to blame. The extension (with planning permission and building approval) was built 24 years ago and he bought his house only some six years ago. Does he have any grounds or should he accept the situation as he came to it? (We don't even accept that the extension plays a role, by the way).

[HowardKennitby]

Did you have this extension built? Did previous neighbours experience flooding? Has there been a significant change in the amount of annual rain where you live?

[jno]

pretty sure he just has to take the situation as he found it. If your extension did cause any change of water flow, you might be liable to the previous owner, but not to the present one.

[Amilcar]

The houses are a pair, built in the 1800s, lying in a bowl of land with his lower than ours. He says someone told him that the water problem in his house began when our extension was built but we have lived here 30 years and know it goes back further than that, maybe, forever. Being higher and properly waterproofed, we have only mild 'old house' damp but he gets lots of water and is not waterproofed. He bought in 2006 without a survey...

[johnny37]

I think you should get a survey and split the cost between you. Maybe your water utility can help.

[buildersmate]

This is the sort of thing that one's household insurance policy (the third party element) covers. So I'd inclined to check with my insurer to see what he says about it, then (if a satisfactory reply) sit back and see what the next-door neighbour does.
I believe that it is the Environment Agency that deals with flooding issues / advice - not the Water Utilities.

[EDDIE51]

Yes as buildersmate thinks this problem is not for the water company to worry about it is the environment agency that deals with it.We are talking about natural ground water not treated piped water or sewage water.
I don't think the neighbour has a case by the way, he should have had a survey done.