ADU rules in Springfield

Table 3.2.210 lists Accessory Dwelling Units (ADUs) as P*, a use permitted subject to SDC 3.2.275, in all three residential districts (R-1, R-2 and R-3), and SDC 3.2.275(B)(3) names constructing a detached accessory dwelling unit on a lot or parcel with a primary single unit dwelling as one of the four ways to establish one. In R-1, Springfield's detached single-unit district, the only gate is that the lot already holds a primary dwelling and meets the 3,000 square foot R-1 minimum lot size. Detached units get a relaxed rear setback of 5 feet where the primary structure needs 10, and are otherwise held to the primary dwelling's clear and objective standards for setbacks, height and lot coverage. R-2 and R-3 work differently: there the right to an ADU is tied to lot area, and a lot larger than 10,000 square feet in R-2, or 4,800 square feet in R-3, may not have one at all.

The definition in SDC 6.1.110 is explicit: an ADU is a dwelling unit secondary to a single unit dwelling, and it may be interior to, attached to, or detached from the primary dwelling. SDC 3.2.275(B) lists converting an attic, basement, garage or any other portion of the primary dwelling, adding floor area to the primary dwelling including a second story, and converting an existing dwelling of under 800 square feet into the ADU while building a new primary dwelling. Attached and interior units follow the same Type 1 review and the same 800 square foot cap as detached ones; what differs is the design menu. Under SDC 3.2.275(G) an ADU within or attached to the main dwelling must either match the primary dwelling (Type 1) or meet the alternative standards (Type 2), because the third option, the clear and objective design standards, is offered only to newly constructed detached units. Converting an existing structure is exempt from the design standards altogether and stays Type 1, although exterior alterations forced by building code must still meet them.

SDC 3.2.275(F)(3) sets one cap and one comparison: the ADU must not exceed 800 square feet or the square footage of the primary dwelling, exclusive of the garage for the primary dwelling, whichever is less. A small primary home therefore yields a small ADU. That comparison is what makes SDC 3.2.275(B)(4) worth knowing: an existing house of less than 800 square feet may be redesignated as the ADU and a larger primary dwelling built on the lot. Nothing else in SDC 3.2.275 limits size directly, but SDC 3.2.275(F)(1) imports all of the primary dwelling's clear and objective standards, so district height (Table 3.2.230: 35 feet in R-1, 50 feet in R-2, none in R-3), setbacks (10 foot front, 5 foot side in R-1, and a reduced 5 foot rear setback specific to ADUs), and lot coverage all apply. Coverage often binds before the 800 square feet does: 45 percent maximum lot coverage on lots of 4,500 square feet or larger, 60 percent maximum impervious surface on lots under 4,500 square feet, and 35 percent maximum impervious surface on lots over 15 percent slope or above 670 feet elevation.

SDC 3.2.275 contains no owner-occupancy standard, and a full-text search of the codified Development Code surfaces only one residential owner-occupancy rule anywhere: SDC 4.7.355(A)(4), which applies to Type 1 short-term rentals, not to ADUs. State law forecloses the question in any event. ORS 197A.425(1)(b)(B) provides that reasonable local regulations relating to siting and design for accessory dwelling units does not include owner-occupancy requirements of either the primary or accessory structure, and Springfield is far above the statute's 2,500 population threshold (it allows all five middle housing types, which ORS 197A.420(2) requires only of cities of 25,000 or more). The city acknowledges the preemption itself: its ADU page explains that Ordinance 6443, adopted May 16, 2022, amended the Development Code to incorporate House Bill 2001. ORS 197A.425(2) preserves one carve-out, allowing local governments to require owner occupancy for vacation occupancies, and Springfield uses exactly that carve-out in its Type 1 short-term rental standard.

Springfield went further than the state ADU preemption and abolished parking minimums outright. SDC 4.6.105(A) opens the parking article with the statement that off-street motor vehicle parking lots or spaces are not required, however if provided must meet minimum standards of the Springfield Development Code. SDC 4.6.125(A) repeats it: although no minimum motor vehicle parking is required, Table 4.6.2 establishes suggested off-street parking standards according to use within any land use district. Table 4.6.2 then flags the ADU exclusion in its own text, listing 2 spaces for each dwelling, not including an accessory dwelling unit, for a detached single-unit dwelling. Because these are suggestions there is nothing to waive and nothing to appeal. Bicycle parking is zero as well: Table 4.6.3 lists single unit dwelling and middle housing at zero required spaces. Independently, ORS 197A.425(1)(b)(B) bars Springfield from requiring additional off-street parking as a condition of ADU approval, and the city's ADU page says House Bill 2001 prevents cities from requiring parking for ADUs. The ADU application does ask you to draw any proposed off-street parking spaces or driveway on the plot plan, but that is a drawing requirement, not a quantity.

SDC 3.2.275(D) provides that an accessory dwelling unit is reviewed under Type 1 procedure except in some cases in the Historic Overlay District, or as provided in SDC 3.2.275(G)(3) when it is reviewed under a Type 2 procedure. Springfield's Type 1 is fully ministerial: the city's ADU Type 1 application packet (revised 12/12/2024) states that this is a Type 1 decision and thus is made without public notice and without a public hearing since there are clear and objective approval criteria and development standards that do not require the use of discretion, with a 30-day target for issuing the decision and no appeal. Two branches shift a project to Type 2, and neither involves a hearing: electing the alternative design standards in SDC 3.2.275(G)(3), or adding an ADU in the Historic Overlay District other than by conversion of an existing structure with no additions, partial demolitions or facade alterations. Under SDC 5.1.415 a Type 2 decision is made by the Director after public notice but without a public hearing unless it is appealed. Land use approval comes first; a building permit and, if required, a Land Drainage and Alteration Permit follow.

Nothing in SDC 3.2.275 or elsewhere in the Development Code limits long-term tenancy of an ADU, and Springfield runs no residential rental licensing program; the city's ADU page lists additional income from renting the ADU as the first benefit of building one. The restrictions attach to short-term use, and they are written around the property rather than around the ADU by name. SDC 6.1.110 defines Short Term Rental, Type 1 as a single unit dwelling occupied by one or more occupants as a primary residence where lodging is provided for compensation for less than 30 consecutive days, for more than 7 days per year, and Type 2 as the same arrangement in a dwelling not occupied as a primary residence. Table 3.2.210 makes Type 1 a permitted use and Type 2 a Discretionary Use in R-1, R-2 and R-3, both subject to SDC 4.7.355. Type 1 caps the operation at 5 or fewer guest rooms and 10 or fewer total occupants, allows at most one full-time-equivalent nonresident employee, limits food service to overnight guests, and requires that the dwelling be occupied by the owner or operator. Type 2 requires at least 400 feet of separation along the same street from another Type 2. Separately, Springfield Municipal Code 7.702 imposes a 4.5 percent transient lodging tax and SMC 7.710 requires every transient lodging provider to register with the tax administrator within 15 days of commencing business and to display a certificate of authority.