Oakland County, MI Environmental Rules: Grading & Drainage (2026)

The Drain Code (MCL 280.1 et seq.) grants the Water Resources Commissioner authority over established county drains. Any owner who wishes to outlet new stormwater into a county drain, cross a drain with a utility, or alter the drain's profile must apply for a Drain Use Permit, submit engineering plans, and post a financial guarantee if construction occurs in the drain right-of-way. Grading plans typically must show: existing and proposed contours at 1-foot intervals, finished floor elevations, lot drainage swales sloping a minimum of 2% away from foundations, and that no drainage is concentrated onto adjacent lots. Detention or retention is sized to the WRC's 2021 standards (WQC, CPVC, CPRC) plus the 100-year flood storm. Most Oakland County cities and townships – including Troy, Farmington Hills, Royal Oak, Novi, and Bloomfield Township – enforce parallel local grading ordinances at the building-permit stage. Lots that drain to a county drain are inspected by the WRC; lots that drain to a municipal storm sewer are inspected by the local engineering department.