Union County, NJ Environmental Rules: Stormwater Management (2026)

Stormwater management in Union County is governed by the NJ Stormwater Management Rules (N.J.A.C. 7:8) and Municipal Separate Storm Sewer System (MS4) permits issued by NJ DEP to all 21 Union County municipalities plus Union County itself. Major development (defined under 2020 NJ DEP amendments as disturbance of 1 acre or more, creation of 0.25 acres or more of regulated impervious surface, or creation/replacement of 0.25 acres of motor vehicle surface) triggers comprehensive stormwater review including Total Suspended Solids removal (80%), Total Phosphorus removal, groundwater recharge, and water quantity control. Minor development adding 400+ sq ft of impervious in many Union County municipalities triggers local review. Elizabeth Revised Ordinances Chapter 13.20 implements MS4 requirements including illicit discharge detection, construction site runoff control, post-construction stormwater management, pollution prevention for municipal operations, and public education. Linden, Rahway, Cranford, Westfield, Summit, and all other Union County municipalities maintain similar stormwater ordinances. The Rahway River and Elizabeth River watersheds are heavily developed with significant combined sewer overflow (CSO) issues in Elizabeth and Linden; NJ DEP CSO permits require Long Term Control Plans. Green infrastructure (rain gardens, bioswales, permeable pavers, green roofs) is incentivized through state grants and local programs. Union County Department of Engineering and Public Works maintains county road drainage systems. Pet waste disposal and grass clipping prohibitions (clippings must not enter storm drains) are standard in all MS4 ordinances.