Sec. 38-1426. – Accessory dwelling units.
(a) The intent and purpose of this section is to allow a relative who wishes to reside in close proximity to his or her family an opportunity to do so by providing authorization to seek and obtain a special exception for an accessory dwelling unit, while maintaining the single-family character of the primary single-family dwelling unit and the neighborhood.

(b) An accessory dwelling unit may be allowed on a lot or parcel as a special exception in any residential or agricultural zoning district (including a residential lot or parcel on an existing planned development). The accessory dwelling unit shall be an accessory use to the primary single-family dwelling unit. Only one (1) accessory dwelling unit may be permitted per lot or parcel. The accessory dwelling unit shall not be constructed prior to the construction and occupation of the primary dwelling unit.

(c)
(1) An accessory dwelling unit shall be occupied initially only by a relative. For purposes of this section, the term “relative” shall mean a sister, brother, lineal ascendant or lineal descendant of the owner of the lot or parcel on which the primary single-family dwelling unit is located (or the owner’s spouse).
(2) Subject to subsection (c)(3), an accessory dwelling unit may be occupied by a nonrelative, provided:
a. The accessory dwelling unit was occupied initially only by a relative and at least three (3) years have passed since the issuance of the certificate of occupancy for the accessory dwelling unit; or
b. The accessory dwelling unit was occupied initially only by a relative, and the relative has died.
(3) The BZA/BCC may impose a condition prohibiting the accessory dwelling unit from being leased, rented or otherwise used or occupied by a nonrelative.
(d) In addition to what is normally required for an application for a special exception, an application for a special exception for an accessory dwelling unit shall contain or be accompanied by the following information and documentation:
(1) An affidavit attesting that the owner of the lot or parcel understands and agrees that the provisions of this section shall be complied with, that he shall be responsible to the county for ensuring that the provisions are complied with, and that he shall be responsible for any failure to comply with the provisions;
(2) Documentation evidencing that the person who is to inhabit the accessory dwelling unit is a relative;
(3) A site plan prepared in compliance with Section 106.1.2 of the Florida Building Code, as amended by Section 9-33 of the Orange County Code;
(4) An exterior elevation drawing of the proposed accessory dwelling unit, regardless of whether it is proposed to be attached or detached;
(5) A photograph and exterior elevation drawing of the primary single-family dwelling unit; and
(e) In order to approve a special exception for an accessory dwelling unit, the county shall determine that the proposed accessory dwelling unit is designed to be similar and compatible with the primary single-family dwelling unit and that it will be compatible with the character of the neighborhood. A manufactured home constructed pursuant to United States Department of Housing and Urban Development standards or a mobile home may not be used as an accessory dwelling unit in any single family residential zoned district.
(f) After an application for a special exception for an accessory dwelling unit is approved, the accessory dwelling unit shall be subject to the following performance standards and requirements:

(1) Ownership. The primary single-family dwelling unit and the accessory dwelling unit shall be under single ownership at all times. Also, either the primary dwelling unit or the accessory dwelling unit shall be occupied by the owner at all times. Approval of an accessory dwelling unit shall not constitute approval for separate ownership or the division of the lot or parcel. Any request to divide the lot or parcel shall comply with and be subject to applicable laws, ordinances and regulations, including zoning regulations and access requirements.

(2) Change in occupancy. The owner shall notify the zoning department in writing whenever there is a change in occupancy of the accessory dwelling unit and inform the zoning department whether the new occupant is a relative or a non-relative.

(3) Living area. The minimum living area of an accessory dwelling unit shall be four hundred (400) square feet. However, the maximum living area of an accessory dwelling unit shall not exceed forty-five (45) percent of the living area of the primary dwelling unit or one thousand (1,000) square feet, whichever is less, and shall not contain more than two (2) bedrooms. For lots/parcels equal to or greater than two (2) acres, the maximum living area shall be one thousand five hundred (1,500) square feet.

(4) Lot or parcel size. The size of the lot or parcel shall be equal to or greater than the minimum lot area required for a single-family dwelling unit in the zoning district. An attached accessory dwelling unit may only be constructed on a lot or parcel whose area is equal to or greater than the minimum lot area required in the zoning district. A detached accessory dwelling unit may only be constructed on a lot or parcel whose area is at least one-and-one-half (1½) times the minimum lot area required in the zoning district.

(5) Open space. An accessory dwelling unit shall be treated as part of the impervious surface area of a lot or parcel. The open space requirements for a single-family lot or parcel shall be met notwithstanding the construction of an accessory dwelling unit.

(6) Setbacks. The setbacks for an attached accessory dwelling unit shall be the same as those required for the primary dwelling unit. In addition, a detached accessory dwelling unit shall be located only to the side or rear of the primary dwelling unit and shall be separated from the primary dwelling unit by at least ten (10) feet, and the distance separation shall not be less than the distance required under Section 610 (“Buildings Located on the Same Lot”) and Table 600 of the 1991 edition of the Standard Building Code, as it may be amended from time to time. Moreover, a one-story detached accessory dwelling unit shall be setback a minimum of ten (10) feet from the rear property line and shall meet the minimum side setbacks for a primary structure in the zoning district. A two-story detached accessory dwelling unit located above a detached garage shall meet the setbacks for the primary structure in the zoning district.

(7) Entrance. An attached accessory dwelling unit may either share a common entrance with the primary dwelling unit or use a separate entrance. However, a separate entrance shall be located only to the side or rear of the structure.

(8) Parking. One (1) additional off-street parking space shall be required for an accessory dwelling unit. The additional space requirement may be met by using the garage, carport or driveway of the primary dwelling unit.

(9) Water and sewer. Adequate water and wastewater capacity shall exist for an accessory dwelling unit. Approval of a special exception for an accessory dwelling unit shall not constitute approval for use of a septic system and/or a well. If a septic system and/or a well must be utilized, applicable laws, ordinances and regulations shall control. The owner of an accessory dwelling unit may apply for and obtain a separate water meter subject to the unit connecting to Orange County’s water system.

(10) Electrical. The owner of an accessory dwelling unit may apply for and obtain a separate power meter subject to the approval of the utility company and complying with all applicable laws, ordinances and regulations.

(11) Impact fees and capital fees. The impact fees for an accessory dwelling unit shall be accessed at the multi-family rate. Water and wastewater capital fees for the accessory dwelling unit shall be assessed at the multi-family rate.

(12) Other laws, ordinances, and regulations. All other applicable laws, ordinances and regulations shall apply to the primary dwelling unit and the accessory dwelling unit.
(Ord. No. 95-21, § 2, 7-25-95; Ord. No. 98-37, § 27, 12-15-98; Ord. No. 2008-06, § 24, 5-13-08)

Source – https://www.municode.com/library/fl/orange_county/codes/code_of_ordinances?nodeId=ORCOCO_CH38ZO_ARTIXGESURE_S38-1426ACDWUN