Folks

Wonder if anyone knows best solution. I purchased my house 13years
ago. The previous neighbor paved 3/4 of his yard 25 years ago. The
pitch of the yard is directed into my yard. Approx. 6-10 times a
year my back portion of my yard floods. The previous neighbor has
sold to a new family...they have 4-6 cars on the paved area I wonder
what the run off is carring with it ie. oil etc. Is this legal and
if so what is my best remedy...my gardener suggested a pumping
system...$8,000.00 + maint. Please help