ADU rules in Upper Darby

A new backyard cottage cannot be built in Upper Darby. Section 550-17B(1) allows an accessory dwelling only where it is 'physically connected to the principal dwelling unit' or is 'a converted existing detached building which maintains the same footprint,' so the detached pathway is a conversion of a garage or other existing outbuilding with no enlargement of its footprint. Even that requires a special exception: Table 3-1 of the Table of Permitted Uses marks 'Accessory dwelling' as S in all six residential districts (R-C, R-C-1, R-1, R-2, R-3, R-4) and leaves the cell blank in C-1 through C-4 and REC, where the use is therefore prohibited. Section 550-17B(3) limits the host property to a single-family detached or single-family semidetached dwelling, which excludes the row homes, twins-over-twins and apartment buildings that make up much of the Township, and B(7) requires a detached unit to use the principal dwelling's existing driveway with no new driveway created.

An attached or internal accessory dwelling (an addition or an in-law suite carved out of the house) is the primary pathway, but it is never by right. It is a special exception in every residential district under Table 3-1, so it takes a noticed Zoning Hearing Board hearing. Section 550-17B(3) allows the unit only in a single-family detached or single-family semidetached dwelling, B(4) requires it to share the principal dwelling's sewage disposal and water supply systems (no separate service laterals), B(5) caps occupancy at two people, and B(2) limits those occupants to people related by blood, adoption or marriage to the occupants of the principal dwelling. B(6) requires compliance with the minimum space and habitable living area rules of the applicable housing and building codes. The practical result is a family suite, not an independent rentable second unit.

Section 550-17B contains no floor-area standard at all, and a full-text scan of Chapter 550 finds no other size rule aimed at accessory dwellings. What constrains size instead is § 550-17B(1)'s requirement that a converted detached building 'maintains the same footprint,' § 550-17B(5)'s two-person occupancy cap, and § 550-17B(6)'s floor of the minimum habitable-space rules in the applicable housing and building codes. Envelope rules do the rest: § 550-40A caps any accessory building at 15 feet in height, and the district tables cap principal buildings at 35 feet with maximum building coverage of 20 percent to 30 percent in R-C, R-C-1, R-1 and R-2 (Table 4-1). Because there is no numeric ceiling, an applicant should expect the Zoning Hearing Board to size the unit through the § 550-54J discretionary criteria and the conditions it may attach under § 550-54J(3).

Chapter 550 contains no clause requiring the property owner to live on the lot, and the ADU standards are written against the occupants of the principal dwelling rather than its owner. Do not read that as freedom, though, because a stricter rule takes its place: § 550-17B(2) limits accessory dwelling occupancy to 'persons who are related by blood, adoption or marriage to the occupants of the principal dwelling unit.' A landlord who lives elsewhere therefore cannot place an unrelated tenant in the ADU; the occupant must be family to whoever lives in the main house. Separately, if the owner does not live on the property, the Township's Rental Dwelling License program applies to the whole arrangement: the official Housing (Rentals) page states the Township treats any property not occupied by the individual listed on the deed as a rental 'regardless of whether rent is paid or whether the occupants are family members.' Pennsylvania has no statewide ADU law that would preempt or soften any of this.

Table 8-1 in § 550-33A lists 'One- and two-family dwellings: 2 spaces per dwelling unit' and has no line for an accessory dwelling, so whether the Zoning Hearing Board counts the ADU as an additional dwelling unit and demands two more spaces is not settled by the text. The table's catch-all, 'All other uses not listed: 1 space per 150 square feet of floor area,' is drafted for nonresidential uses and would produce an absurd result if applied to a family suite; treat it as a question to raise with the Zoning Officer rather than an answer. What is certain is § 550-17B(7): 'If the accessory dwelling unit is located in a detached building, the accessory dwelling unit must utilize the existing driveway for the principal dwelling on the property, and no new driveways shall be created or installed.' Section 550-33B(5) separately prohibits parking in the front yard in all residential districts, and B(7) requires driveways to be paved with a solid surface.

Every accessory dwelling in Upper Darby needs a discretionary Zoning Hearing Board approval. Table 3-1 marks the use S, defined in § 550-8A as 'a use that is permitted only by approval by the Zoning Hearing Board,' and § 550-53A confirms that permits for special exception uses 'shall be issued only upon order of the Zoning Hearing Board.' The Board holds a public hearing noticed by publication once a week for two successive weeks plus mailed notice to the applicant, the Mayor, Council, the Zoning Officer and the Delaware County Planning Department (§ 550-54G), and it weighs the open-ended criteria in § 550-54J, including neighborhood character and the effect on adjacent property, with power to attach conditions. The Township's current application form (Zoning Hearing Board Petition for Variance or Special Exception, version 5.28.26) lists a nonrefundable residential fee of $750 for up to two reliefs. An approval expires after one year if no building permit is obtained (§ 550-54H); after approval the applicant still needs a zoning use permit and a zoning certificate of occupancy under § 550-53B, C and E.

Section 550-17B(2) restricts accessory dwelling occupancy to 'persons who are related by blood, adoption or marriage to the occupants of the principal dwelling unit,' and § 550-17B(5) caps the unit at two occupants; the § 550-56 definition of 'accessory dwelling' repeats the restriction (in slightly narrower terms, omitting marriage). Renting to a non-relative is therefore a zoning violation, enforceable under § 550-53F and G. Upper Darby has no short-term rental ordinance anywhere in its Code, and transient lodging is handled as a commercial use: 'hotel or motel' is defined in § 550-56 as accommodations 'available for temporary rental to transients,' and Table 3-1 permits hotel/motel and bed-and-breakfast inn only in C-2, C-3 and C-4, never in a residential district, so listing an ADU nightly is not an authorized use where ADUs exist. Money changing hands is not what triggers licensing: Chapter 417 § 417-10 adopts the 2015 IPMC with a locally added Chapter 9, whose § 901.1 and § 902.1 require an annual Rental Dwelling License and pre-occupancy inspection for every dwelling unit that is rented, leased or let out, and the Township's Housing (Rentals) page applies that to any unit 'occupied by someone other than the owner,' expressly 'regardless of whether rent is paid or whether the occupants are family members.' Licenses run one year, are not transferable, and can be suspended for code violations.