Neighbor's downspout causing water in our basement...

We live on a steep hill.  The previous owners reported little if any water problems in the basement, and once we rerouted our gutters towards the driveway instead of the house, we have had NO water in our basement for the 3 years we've lived here.  Our new neighbors on the uphill side of us have just rerouted one of their downspouts to direct water across their driveway; with the rain today, there was essentially a river going from their new downspout across their driveway, directly under our porch which has resulted in about two inches of water in our basement.  We've had heavier rain than today in the past three years with no water in the basement, so I can only assume the neighbor's new gutters are the culprit. 

We've never had this issue before so I don't quite know how to proceed.  Is this now OUR problem, where we would have to create some kind of trench on our property to divert the water from their gutter away from our house?  Or is this something I could in good faith ask them to adjust, if possible?  I don't want to cause them problems as they've had a lot to deal with with their new house...but at the same time we're strapped for cash and really don't want another project on our plate that we weren't planning for.  

Thanks for any advice!

I hope you have the sort of neighbor who cares.  I know I went through some trouble around my house to make sure that all of my gutters drain into the stream behind my house.  Seems like the considerate thing to do.

As far as I know they are not allowed to redirect water that results in said redirected water ending up on your property.

They should definitely fix it, and I'm glad they are stepping up. We unwittingly created a similar problem for our downhill neighbor in West Orange, and it took her years to let us know. I felt terrible, even though I had no clue up to that point.

Congrats on the quick fix, so frustrating of course to get water again. We have had repeated issues from neighbor uphill constantly redoing landscaping that results in literally dirt with water flowing over the existing cement trench between the property so it blocks up water going down the trench and pours over and into our basement. We finally took on fixing it, however, if it happens again, fully plan to inform the neighbor. Houses are too close to not insist when doing any modifications to property to check and consider whether they thought through water or worse, dirt. They thought building up their side and putting a wood slat type fence was going to hold stuff in place. Need a real plan to have one side higher than another. We brought in landscape expert to consult and solve it. Any new work, will raise need to address it before work is done.

Ugh, sounds like a pain, truegrid. We are very lucky with the new neighbors; it was an honest mistake on their part and they fixed it that night, in the dark, before more rain came. It's hard because we are on such a steep hill. I hope your situation can get rectified without too much expense!