Stormwater Management: Newark vs Wilmington
How do stormwater management rules compare between Newark, DE and Wilmington, DE?
Newark and Wilmington have similar restriction levels.
Newark, DE
New Castle County
New Castle County enforces stormwater management under Delaware's Sediment and Stormwater Program (7 Del.C. Chapter 40 and DNREC Delegation) administered by the New Castle Conservation District (NCCD). Projects disturbing 5,000+ sq ft or adding 5,000+ sq ft of impervious surface require an approved sediment and stormwater plan. Post-construction BMPs (bioswales, rain gardens, infiltration) are mandatory. NCC holds MS4 permit under Clean Water Act.
View full Newark rules →Wilmington, DE
New Castle County
Wilmington enforces stormwater management standards along Brandywine Creek and Christina River drainage areas, requiring runoff controls for new construction, redevelopment, and impervious-surface expansions exceeding state and county thresholds.
View full Wilmington rules →Key Facts Comparison
| Fact | Newark | Wilmington |
|---|---|---|
| State Law | 7 Del.C. Ch. 40 | - |
| Administered By | NCCD delegation | - |
| Trigger | 5,000 sq ft disturbance | - |
| Preferred BMPs | LID / green infrastructure | - |
| MS4 Permit | Yes, under CWA | - |
| Threshold | - | 5,000 sq ft disturbance |
| Authority | - | DE Title 7 Ch. 40 |
| Local partner | - | New Castle Conservation District |
| Watersheds | - | Brandywine; Christina |
Highlighted rows indicate differences between cities.
Newark FAQ
Do I need a stormwater plan for my home addition?
If the addition disturbs more than 5,000 square feet of land or adds more than 5,000 square feet of impervious surface, yes. The New Castle Conservation District reviews these plans. Smaller projects may still need erosion control but not full stormwater management.
Can I wash my car in the driveway?
Residential car washing using biodegradable soap with runoff into a pervious area (lawn) is generally allowed. Washing on a driveway with soapy runoff entering a storm drain is a prohibited illicit discharge to the MS4 system.
Wilmington FAQ
Do I need a stormwater permit for a small home addition?
Single-family additions disturbing under 5,000 square feet generally do not require a state stormwater plan, but local grading rules still apply.
Who inspects my detention basin?
The owner is responsible for maintenance; Wilmington Public Works and the Conservation District may inspect periodically and order repairs.
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