ADU rules in Bethlehem

Bethlehem's Zoning Ordinance contains no accessory dwelling unit use at all. The only second unit the code allows beside a house is a 'Unit for Care of Relative', which Section 1304.01(b)(5) marks 'P' (permitted by right, decided by the Zoning Officer) in every residential district: RR Rural Residential, RS Single Family, RG Medium Density, RT High Density and R-RC Residential Retirement Complex. It may be detached: Section 1322.03(bbb)(3) expressly contemplates 'a modular cottage that will be completely removed from the lot after the relative no longer resides within the unit' and allows a lawful detached garage to be converted into one. The conditions bite hard: occupancy is capped at two people who must be relatives of the permanent residents of the principal dwelling, at least one of whom needs the accommodation because of illness, old age or disability, and the unit must be reconvertible or removable once they leave. New since August 4, 2026: Ordinance 2026-22 added Section 1318.26(e), 'No more than one single-family detached dwelling may be located on a lot', and because Section 1302.40(a) defines a single family detached dwelling as 'A building occupied by only one dwelling unit, and having no party wall in common with an adjacent building' while Section 1302.146 calls the relative-care unit 'A dwelling unit', a free-standing cottage now has to be squared with that new rule; the accessory-use listing and the modular-cottage language were left untouched, so confirm with the Zoning Officer before planning a detached unit. Outside residential zones the same accessory use is permitted on the lot of an existing dwelling in the CL, CG, CB and IR districts.

The same Unit for Care of Relative may be attached or internal, but Section 1322.03(bbb)(8) requires 'an internal doorway that connects the main dwelling unit to the unit for the relative' and (9) allows only one entry door facing a public street, so it cannot read as an independent apartment. A genuinely separate second dwelling unit is possible only through 'Conversion of an Existing One Family Dwelling into Two or More Dwelling Units', and that is a special exception before the Zoning Hearing Board available only in the RG and RT districts (not permitted in RR, RS or R-RC). Section 1322.03(o)(6) limits it further: 'If the building is currently a one family dwelling, it shall not be converted to two or more dwelling units unless the building included more than 3,000 square feet of habitable floor area prior to the enactment of this Ordinance.' Section 1302.41 also bars a second kitchen in a dwelling unit 'unless it is for the purpose of accommodating a relative who needs special care and supervision because of age or disability', which closes the informal internal-ADU route. Ordinance 2026-22 of August 4, 2026 left both routes untouched, and its new one-house-per-lot rule in Section 1318.26(e) reaches only detached dwellings, so an attached or internal relative-care unit is unaffected by it.

Section 1322.03(bbb) sets no floor-area cap of its own, so the binding limit for a detached Unit for Care of Relative is the general accessory building rule in Section 1306.03(d): 'In no case shall the floor area of an accessory building exceed 1,000 square feet in a residential district.' Occupancy is the tighter constraint in practice: a maximum of two persons under Section 1322.03(bbb)(2). Detached accessory structures take a 2 foot minimum side and rear setback under Section 1306.03(b) and may not sit between the principal building and the front lot line. On the conversion path the ordinance sets minimums rather than maximums: one unit must have at least 700 square feet of habitable floor area, with additional units at 500 (one-bedroom), 700 (two-bedroom) or 900 (three-bedroom) square feet, on top of the 3,000 square foot pre-existing-building threshold. District lot area, coverage and height standards in Article 1306 continue to apply, and Ordinance 2026-22 of August 4, 2026 changed no dimensional standard.

The unit exists only to house a relative of the household in the main house, and that tie is policed annually. Section 1322.03(bbb)(2) requires the accessory unit to be 'occupied by a maximum of two persons, who shall be "relatives" of the permanent residents of the principal dwelling unit', and (5) provides that 'The owner of the property shall be required to annually renew the permit for the use', conditioned on a written statement that the relative still lives there. Section 1322.03(bbb)(4) additionally requires the owner to record a legally binding mechanism, binding on future owners, barring use as a separate dwelling unit once the relative leaves. Strictly read, the text ties occupancy to the permanent residents of the principal dwelling rather than naming the owner, but the owner carries the annual certification and deed-restriction duties, so there is no way to build one and live elsewhere. Pennsylvania still has no ADU statute preempting any of this, re-checked against the General Assembly's own bill records on August 28, 2026.

Article 1319.01(a)(1)(i) requires 'two parking spaces for each dwelling unit' outside the CB Central Business District, where no off-street parking is required at all. For a relative-care unit that default is waivable: Section 1322.03(bbb)(7) provides that 'Additional parking for the accessory unit is not required if the applicant proves that the resident(s) of the accessory unit will not routinely operate a vehicle', which is often satisfiable given the illness, old age or disability precondition. There is no transit-proximity reduction. A conversion into additional dwelling units gets no such relief: Section 1322.03(o)(8) requires that 'All parking requirements shall be met for the total number of dwelling units', and (o)(7) requires plans showing the parking and its access.

A Unit for Care of Relative is by-right: the residential use table in Section 1304.01(b)(5) marks it 'P' in all five residential districts, and the table legend defines 'P = Permitted by right use (zoning decision by Zoning Officer)'. There is no hearing, but the review is not a rubber stamp. The applicant must prove to the Zoning Officer under Section 1322.03(bbb)(3) that the unit can be easily reconverted into part of the principal dwelling or is a removable modular cottage, must record the binding restriction under (4), must keep the unit from decreasing the residential appearance of a one family dwelling under (6), and must renew the permit every year under (5). By contrast, the conversion of a house into two or more dwelling units is a special exception decided by the Zoning Hearing Board and only in the RG and RT districts, so a homeowner who wants a genuinely independent second unit does face a hearing.

A Unit for Care of Relative may not be let to a tenant. Section 1322.03(bbb)(2) limits occupancy to two relatives of the principal dwelling's permanent residents, and (4) requires 'a legally binding mechanism in a form acceptable to the City that will prohibit the use of the accessory unit as a separate dwelling unit after the relative no longer resides within the unit', binding on future owners. Short-term rental is shut down twice over. Article 1741.03 provides that 'Short Term Lodging is prohibited throughout the City of Bethlehem' except two owner-occupied arrangements, renting no more than 2 bedrooms in an owner-occupied single family dwelling with the owner present, or renting the owner's own primary residence for a minimum of 7 consecutive days and no more than 30 days per calendar year, both under an annual Short Term Lodging License; Section 1741.04(C)(2) is explicit that the rented bedrooms 'must be located within the principal dwelling unit and not in an accessory building'. On top of that, Ordinance 2026-22 (adopted August 4, 2026) rewrote the zoning definition of 'hotel' so that 'An establishment which has sleeping accommodations available to the general public as rooms, suites or other sleeping quarters for periods less than 30 consecutive days is a hotel within the meaning of this definition', added a 'Transient guest(s)' definition covering stays 'for a period of less than 30 consecutive days', and provided that no sleeping quarter in a hotel 'shall be considered a dwelling unit'; hotels are not a listed use in any residential district, and the assistant city solicitor's transmittal memo states the change has 'the effect of excluding short-term rentals in residential districts where hotels are prohibited'. Lawful rental dwelling units otherwise need a residential rental license and periodic inspection under Article 1738.