ADU rules in Ashland

Ashland's zoning code allows a second dwelling on a single-family lot in one district only: in R-E Residential Estate, residential accessory uses "may also include secondary dwelling units (guest house, caretaker's quarters)" as a by-right accessory use. Every other district keeps the general rule of one single-family building plus its accessory structures per zoning lot, and the code has no accessory dwelling unit, accessory apartment or garage apartment use. R-E is a large-lot estate district (20,000 sq ft minimum lot, 100 ft width) meant for remote or steep land, so most city lots in R-12, R-6, R-5 and R-4 cannot add a detached unit.

The code has no attached or internal ADU use. In R-E the secondary dwelling unit allowance in § 157.040(A)(9) does not say whether the unit must be detached, so a guest or caretaker unit may be possible within or attached to the house there. Elsewhere the only route to a second unit inside a house is converting it to a two-family dwelling (duplex): permitted by right in R-5, R-4 and B-3 (on 2,500, 2,000 and R-4-equivalent lot area per unit), a Board of Zoning Adjustment conditional use in R-6 limited to lots at the fringe abutting incompatible uses, and not allowed in R-12. A duplex is two principal units, not an accessory unit.

Neither the code nor the city's July 2026 zoning PDF sets a floor-area cap for an R-E secondary dwelling unit. The definition of an accessory structure or use requires it to be "subordinate in area, extent or purpose" to the principal building, and the R-E dimensional row caps lot coverage at 25 percent (principal plus accessory structures) with a 45 ft height limit. Detached accessory structures stay out of the required front yard, at least 4 ft from side and rear lot lines and 10 ft from the principal building. The 400 sq ft figure in the 2026 Tiny Home definition applies to a principal dwelling, not an accessory unit.

Nothing in Chapter 157 or the July 2026 zoning PDF requires the owner to live on an R-E lot with a secondary dwelling unit, or in either half of a duplex. The only owner-residency rule in the zoning code applies to bed and breakfast facilities, which need a resident owner-operator and a conditional use permit that lapses on sale. The secondary unit must serve "the convenience and necessity of the principal residential use", which ties it to the main home but does not require owner occupancy.

The parking schedule requires "1 space per unit" for dwellings (including mobile homes) in every district except B-3 Downtown Business, so an R-E secondary dwelling unit or the second unit of a duplex needs its own space. The schedule applies to new buildings and uses and to expansions of 30 percent or more. The code has no ADU-specific parking exemption.

In R-E, accessory structures and uses, including the secondary dwelling unit, are marked "P" (use by right) in the use table, so the route is the zoning and building permit process with Zoning Administrator review rather than a hearing. Duplex conversions are also by right in R-5, R-4 and B-3, but need a Board of Zoning Adjustment conditional use permit in R-6. Outside R-E, R-6, R-5, R-4 and B-3 no second unit is allowed at all.

Chapter 157 does not say whether an R-E guest house or caretaker unit may be rented, though it must serve the principal residential use; the code's dwelling unit definition contemplates "owner occupancy, or rental or lease". Ashland has no short-term rental licensing or zoning ordinance. Nightly lodging in a home is regulated through the bed and breakfast use, a conditional use in R-5 only, with a resident owner-operator, at most four units in one structure, stays of up to seven consecutive days and a guest log. Longer room rentals fall under the boarding or rooming house use (3 to 9 people).