New Castle County, DE Accessory Structures: Tiny Homes (2026)
Tiny home rules in New Castle County, DE, covering tiny houses on wheels (THOWs), park model RVs, and tiny home on foundation builds, determine where they are legal and how they get permitted.
Key Facts
- Minimum size
- 400 sq ft gross floor area
- Maximum size
- under 750 sq ft GFA
- Standalone use
- not permitted on ordinary lots
- Allowed paths
- ADU or Pocket Neighborhood only
- Wilmington/Newark
- separate city codes, not covered
Summary
New Castle County zones tiny homes as "small single-family detached dwellings," a defined use capped at under 750 square feet and allowed only as an ADU or inside a permitted pocket neighborhood.
Dwelling, small single-family detached. A one (1) or two (2) story dwelling unit, designed for and occupied by not more than one (1) family and having no roof, wall or floor in common with any other dwelling unit. A. It has a minimum of four hundred (400) square feet of gross floor area and less than seven hundred fifty (750) square feet of gross floor area. B. It is of light-frame or masonry construction and permanently mounted on a solid foundation or pier foundation system in accordance with Chapter 6.
Official source re-checked September 7, 2026: no newer edition of the code had been published (publisher’s edition: Code of Ordinances: Supplement 5).
Full Breakdown
The Unified Development Code defines a "small single-family detached" dwelling as 400 to under 750 square feet of gross floor area, permanently foundation-mounted, with continuous weather-resistant siding (Sec. 40.33.300). Table 40.03.110 does not let you build one as a standalone home on an ordinary lot: it's a limited-review use in only a handful of districts (TN1, ST, S3, NC2) and the table's own standards column states it is "Only permitted in as an ADU Section 40.03.410, or in a Pocket Neighborhood" under Sec. 40.25.333. As an ADU it must share a lot with a full-size principal dwelling, the owner must occupy one of the two units, and it needs a Department building permit under Chapter 6. This is unincorporated New Castle County zoning; Wilmington and Newark run their own separate zoning and building codes not covered here.
Violations & Fines
Placing a small/tiny dwelling on a lot without qualifying it as an ADU (Sec. 40.03.410) or as part of an approved Pocket Neighborhood (Sec. 40.25.333) is a zoning use violation subject to the Department's UDC enforcement and permit denial; occupying one under 400 square feet of GFA fails the code's own size floor.
Frequently Asked Questions
Can I put a tiny home on my New Castle County lot as a standalone house?
What size counts as a small single-family dwelling under the code?
Sources & Official References
Other rules in New Castle County
Compare New Castle County to another location·View the Delaware accessory structures overview
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