Newport Beach, CA Environmental Rules: Grading & Drainage (2026)

NBMC Title 15 establishes grading permit requirements for excavation, filling, and earth-moving activities. Grading permits are required for cuts or fills exceeding 50 cubic yards, excavations deeper than 5 feet, fills higher than 3 feet, or any grading on slopes steeper than 3:1. A soils and geology report prepared by a licensed geotechnical engineer is required for most grading permits. Drainage plans must demonstrate that post-development runoff rates do not exceed pre-development rates and that drainage is directed to approved outlets without adversely affecting neighboring properties. The city requires on-site retention or detention for projects that increase impervious surface area. Building pads must be graded to drain away from foundations with minimum 2% slopes. Retaining walls exceeding 3 feet in height require separate structural permits. Properties in hillside areas are subject to additional slope stability analysis and may need engineered drainage systems. The city engineer reviews all grading plans for compliance with the Municipal Code and California Building Code. Grading security deposits may be required to ensure completion and site restoration. Inspections occur at multiple stages including rough grade, drainage installation, and final grade.