re: Recommendations needed for subsurface drainage contractors on the Northshore.

NS has terrible soils. Many yards I worked to redesign always had major drainage challenges because of the soil. Water will just sit for days until it percolates into the ground

Grassmasters is a pretty good one on the north shore
Mullin Landscape and Smoketree are two big ones that work on the northshore.

Greenman Dan specializes in drainage work, but I am not sure of he works on the northshore