Agenda Packet 2-20-19 Work Session

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ADU Guidance ‐2‐ March 2018 Guidance by Topic The purpose of the following guidance is to help cities and counties implement the ADU requirement in a manner that meets the letter and spirit of the law: to create more housing in Oregon by removing barriers to development. Number of Units The law requires subject cities and counties to allow “at least one accessory dwelling unit for each detached single‐family dwelling.” While local governments must allow one ADU where required, DLCD encourages them to consider allowing two units. For example, a city or county could allow one detached ADU and allow another as an attached or interior unit (such as a basement conversion). Because ADUs blend in well with single‐family neighborhoods, allowing two units can help increase housing supply while not having a significant visual impact. Vancouver, BC is a successful example of such an approach. Siting Standards In order to simplify standards and not create barriers to development of ADUs, DLCD recommends applying the same or less restrictive development standards to ADUs as those for other accessory buildings. Typically that would mean that an ADU could be developed on any legal lot or parcel as long as it met the required setbacks and lot coverage limits; local governments should not mandate a minimum lot size for ADUs. So that lot coverage requirements do not preclude ADUs from being built on smaller lots, local governments should review their lot coverage standards to make sure they don’t create a barrier to development. To address storm water concerns, consider limits to impermeable surfaces rather than simply coverage by structures. In addition, any legal nonconforming structure (such as a house or outbuilding that doesn’t meet current setback requirements) should be allowed to contain, or be converted to, an ADU as long as the development does not increase the nonconformity. Design Standards Any design standards required of ADUs must be clear and objective (ORS 197.307[4]). Clear and objective standards do not contain words like “compatible” or “character.” With the exception of ADUs that are in historic districts and must follow the historic district regulations, DLCD does not recommend any special design standards for ADUs. Requirements that ADUs match the materials, roof pitch, windows, etc. of the primary dwelling can create additional barriers to development and sometimes backfire if the design and materials of the proposed February 20, 2019, Work Session – Item 1