HB 2138 (expanding middle housing) Mandatory Code Amendments

Oregon State Legislature website: https://olis.oregonlegislature.gov/liz/2025r1/Measures/Overview/HB2138

House Bill 2138 made numerous changes regarding substantive requirements for middle housing. Cities are required to comply starting on January 1, 2027. These changes include:

1. Duplexes. Cities are required to allow not just attached, but also detached duplexes. Sandy already allows detached duplexes, but HB 2138 will now prevent Sandy from prohibiting them in the future.
2. Single Room Occupancies (SROs). This is an unfamiliar term to many (it was introduced by the legislature in 2023) which refers to “A residential development with no fewer than four attached units that are independently rented and lockable and provide living and sleeping space for the exclusive use of an occupant, but require that the occupant share sanitary or food preparation facilities with other units in the occupancy.” It has been described as similar to a dorm. These are already allowed in Sandy as required by existing law, but HB 2138 made several significant changes. For one, SROs must now be allowed to be detached, rather than just attached. It is unclear what that is intended to look like, but in theory it could look a lot like a cottage cluster, but without individual kitchens and instead some sort of share kitchen facility. In addition, the bill increases the number of units allowed for an SRO in a multi-unit zone to be three times the maximum unit density of the zone.
3. Bonus units. When one or more of the units in a middle housing development are accessible or affordable, HB 2138 requires cities to allow an additional bonus unit. This means that, in these circumstances, the City will be required to allow triplexes rather than just duplexes.
4. Retention of existing units. The City will now be required to allow an existing unit on a property to be retained when a middle housing development is proposed. In other words, when a property has an existing single-family dwelling, the owner may be able to build a duplex on the property and keep the single-family dwelling, provided the new duplex complies with siting and design standards.