Plainfield, NJ Environmental Rules: Grading & Drainage (2026)

Grading and drainage regulation in Union County combines NJ Uniform Construction Code (N.J.A.C. 5:23) requirements with local zoning and engineering ordinances plus NJ DEP Flood Hazard Area Control Act Rules (N.J.A.C. 7:13) where applicable. Elizabeth Revised Ordinances Chapter 15.04 requires grading permits for excavation or fill exceeding 50 cubic yards; plans must show existing and proposed contours, drainage patterns, erosion control, and impact on adjacent properties. Westfield Land Use Ordinance §13.14 requires site plan review for grading affecting drainage or exceeding threshold volumes. Summit, Cranford, and other municipalities have similar provisions. A fundamental principle under NJ common law and codified in most municipal ordinances is that property owners cannot redirect natural surface drainage onto neighboring properties in a concentrated or increased manner; the Armstrong v. Francis Corp. (1956) rule permits reasonable development but prohibits undue harm to neighbors. Retaining walls over 4 ft require engineered plans and building permits under NJ UCC; walls over 6 ft typically require additional geotechnical review. Soil compaction testing is required for structural fill supporting buildings or critical infrastructure. Driveway slopes typically capped at 12-15% maximum. In FEMA-designated floodplains (significant portions of Elizabeth, Linden, Cranford along Rahway River, Union Township, and lower-lying areas) any grading requires NJ Flood Hazard Area permit plus local flood damage prevention ordinance compliance. Union County Engineering reviews work affecting county roads (Springfield Avenue, Morris Avenue, various others). Sinkholes and karst geology are not typical in Union County (contrast Warren, Sussex) but brownfield contamination constrains grading in industrial areas.