ADUs are allowed in Unincorporated New CastleTypes:DetachedInternal
Types:DetachedInternal
Accessory Dwelling Unit (ADU) Rules for Unincorporated New Castle, DE
Is your property eligible for an ADU?
# of Properties
148,675
Owner-occupied
77%
Zoning districts
38
Median Lot Size
0.22 acres
Avg Income
$115,866
Residential Types:
148,675 housing units
Other
100%
Zoning Districts:
151,739 parcels · 38 districts
NC6.5
29%(43,500)
NC21
13%(19,552)
S
11%(17,240)
NC5
8%(12,821)
Other
39%(58,626)
ADU Rules
What can you build in Unincorporated New Castle, DE?
Unincorporated New Castle, DE follows state and local rules for Accessory Dwelling Units. Here is a concise overview of the local rules.
Eligibility
- –Internal / Attached ADU: By Right
- –Detached ADU: By Right
Detached ADU Size Limits
- –For lots under 1 acre, a detached ADU’s floor area may not exceed the principal dwelling’s footprint; detached ADUs are not permitted on lots smaller than 0.5 acre; no size cap is stated for lots 1 acre or larger.
Max Units
- –Single-family detached: 1 ADU/lot (internal/attached; detached only if lot ≥0.5 ac).
- –Townhouse/duplex/multifamily: none specified.
Owner Occupancy
- –Owner must reside in either the principal dwelling unit or the ADU.
Parking
- –1 space per ADU; garage may count toward required off-street parking; Transect districts may impose different per-dwelling minimums
Rental Restrictions
- –Only one of the two dwelling units on the lot may be rented at a time; the other must be owner-occupied.
What's allowed on your lot?
These are the municipality-wide rules. What's allowed on a specific property also depends on state laws, setbacks, floor area ratio, lot coverage, environmental constraints, topography, and other property-specific factors. Search your address on FutureLot to see what's allowed on your property.
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ADU rules in other Delaware municipalities
Rules change at the town line. Check the municipality your property is actually in.
New Castle County
Browse addresses by ZIP in Unincorporated New Castle
1972018,121 addresses1970216,550 addresses1970916,372 addresses1970115,054 addresses1980813,898 addresses197119,520 addresses198038,394 addresses198108,301 addresses197138,185 addresses197076,721 addresses198046,467 addresses197345,302 addresses197034,534 addresses198094,463 addresses198053,683 addresses198073,030 addresses19977851 addresses