[HISTORY: Adopted by the Mayor and Council of the City of Harrington 9-15-2025 by Ord. No. 25-06. Amendments noted where applicable.]
The purpose of this chapter is to allow and regulate accessory dwelling units (ADUs) in the City of Harrington to increase the availability of affordable housing; provide housing options for family members, seniors, and caregivers; allow homeowners to utilize existing or new structures efficiently; and maintain the character of the neighborhood while allowing reasonable flexibility.
As used in this chapter, the following terms shall have the meanings indicated:
ACCESSORY DWELLING UNIT (ADU)
A self-contained dwelling unit that is secondary to the principal dwelling unit on a property and includes independent living facilities, such as a separate entrance, bathroom, and kitchen. The dwelling unit may be attached to the principal dwelling (accessory apartment) or detached on the same lot (cottage).
FLOOR AREA
The sum of the gross horizontal areas of the several floors of a dwelling, exclusive of garages, basements, cellars, attics and open porches, measured from the exterior faces of the exterior walls.
OWNER-OCCUPANT
A person who makes either the principal dwelling or the ADU their primary residence.
A. 
ADUs shall be permitted in all residential zones subject to compliance with other applicable regulations and building codes.
B. 
Only one ADU is permitted per lot, whether attached or detached.
C. 
Manufactured homes shall not be permitted as an ADU.
D. 
The property owner must occupy either the principal dwelling or the ADU as their primary residence. A notice and declaration of land use restriction to this effect shall be signed and recorded prior to issuance of a certificate of use and/or building permit for the ADU.
E. 
Any request for an ADU shall conform to all provisions of the Delaware State Plumbing Code, and no dwelling unit that is served by an on-site wastewater disposal system shall be modified to create an accessory dwelling unit until a permit for such has been secured by the Department of Natural Resources and Environmental Control.
F. 
Accessory dwelling units will be charged an additional equivalent dwelling unit (EDU).
G. 
Rental units prohibited.
H. 
An ADU may not be sold separately.
A. 
The maximum size of the accessory dwelling unit shall not exceed 50% of the floor area of the principal dwelling unit. Square footage required to meet accessibility standards shall not count toward the total square footage limit.
B. 
Detached accessory dwelling units shall be constructed on a slab or crawl space. Basements are not permitted.
C. 
Setbacks.
(1) 
Attached accessory dwelling units shall comply with the same setbacks as the principal structure.
(2) 
Detached accessory dwelling units shall be placed behind the principal structure and maintain 1/2 of the principal structure's side and rear setbacks.
D. 
Total lot coverage (impervious cover) is limited to 50%.
E. 
Applications for accessory dwelling units shall also include:
(1) 
Full building plans for entire new structure or addition/renovation.
(2) 
Separate floor layout of all finished levels.
(3) 
Use of all rooms.
(4) 
All entrances/exits.
(5) 
Where applicable, include parking plan for current and future use.
F. 
The Board of Adjustment may consider variances from these provisions in accordance with the standards and procedures established in Chapter 440, Zoning.
G. 
All ADUs must meet current building, health, and fire safety codes, and any other applicable regulations.