Neighbor wants to run drainage through my flip

[Ken Nyczaj]

Hello all,

Recently, a neighbor asked to run drainage from his rear downspout through his yard to the rear of my yard and out to the woods on the rear side of my property line. Claiming the water from the downspout is causing foundation damage on their home. They'll be trenching and running a pipe and adding in two drainage systems to help with any build up of water in my yard all on their dime. This was offered as a thank you, and to help with some stagnate water that does buildup in my yard.

I'm concerned about liability. Legal documents have been drawn up to be signed and witnessed, removing any costs, responsibility, liability from my LLC that holds the property.

Anything else I'm missing? Should there be a contractors license involved? Proof of insurance, etc?