My neighbor redirected a downspout and now rainwater crosses my driveway. How do I discuss impact without arguing about blame?

The first heavy rain after my neighbor’s gutter work left a narrow river across my driveway.

Water came from a new downspout extension along the side of his house. The extension ends near the property line, pointed toward the low section between our garages. From there, the water traveled across the concrete in front of my side door and collected near the steps.

Before the work, that area became damp during storms but did not carry a visible stream. I cannot prove the new extension caused every puddle. I can say the pattern changed immediately after it appeared.

I texted my neighbor a short video and asked whether the installer could look at the direction. He replied that the downspout ends on his property and that water naturally runs downhill. Both statements may be true, but they do not address what I am seeing.

I am trying not to turn this into a boundary or drainage ruling that I am unqualified to make. I do not know what local requirements apply. I also do not want to wait through several storms while the disagreement hardens into “my water” versus “your driveway.”

The neighbor is usually practical. We have shared a ladder and helped each other clear branches. I suspect he hears my message as a demand to redo expensive work based on one storm. What I want first is a joint observation and a professional opinion about whether the outlet can be redirected or slowed without creating another problem.

Rain is forecast again this weekend. I could ask him to meet outside while it is happening so we can watch the path together. I could also contact the contractor directly, but that feels like going around the person who hired them. Calling local services before a second conversation seems premature unless the water reaches the house.

My proposed message is: “I am not asking us to decide responsibility by text. The flow changed after the extension was added, and it is now crossing the driveway by our side door. Can we look at it together during the next rain and ask the installer about options?”

Is that collaborative enough, or too soft for a recurring property impact? At what point should I move from neighbor conversation to independent documentation and professional guidance?