ADU rules in Richmond

Richmond's Development Ordinance (Code Chapter 157) has no accessory dwelling unit, accessory apartment, garage apartment or guest house use, and a phrase search of the whole code returns none of those terms. The residential use table allows only one detached single-family dwelling per lot in R-1A, R-1B, R-1C, R-2, R-3, RE, PUD and AG, and §157.044(I) requires a separate building site for each individual building or use except permitted accessory buildings and uses, so a second detached house behind an existing one is not allowed on a single-family lot. Residential accessory structures (sheds, garages, pools) are allowed, but nothing lets one be used as a dwelling.

There is no ADU use, so an internal or attached second unit is possible only by making the house a two-family (duplex) dwelling. Duplex dwellings are permitted by right in R-2 (Two Family Residential), R-3 (Multi-Family) and PUD zones, and are not allowed in the R-1A, R-1B, R-1C, RE, MP or AG zones that cover most single-family neighborhoods. The duplex must meet the district's lot standards (8,500 sq ft minimum site in R-2; 6,500 sq ft for the first unit plus 2,800 sq ft per additional unit in R-3). Basement and loft apartments are listed only in the B-2 Central Business District (conditional use) and B-3 (loft apartments for business personnel only).

Because Richmond has no ADU category, there is no floor-area cap for a second unit. A duplex in R-2 is governed by the general dimensional table: 8,500 sq ft minimum building site, 60 ft width, 25 ft front, 5 ft side and 20 ft rear setbacks, and 35 ft maximum height; R-3 allows 65 ft. Residential accessory structures are limited to side or rear yards, may cover no more than 25 percent of the yard area, and at most two roofed accessory structures are allowed per lot.

Nothing in the Development Ordinance requires the owner to live in either unit of a duplex, which is the only route to a second unit. The code's definitions treat duplexes, townhouses and multi-family dwellings as ordinary owner-occupied or rental housing. The only owner-related rule is in the short-term rental regime, where the registrant (host) must be the owner of record, and that applies to any dwelling used as a short-term rental, not to second units as such.

Table 157.046.1 sets parking for two-family attached dwellings per unit: 3 bedrooms equals 2 spaces, 4 to 5 bedrooms 3 spaces, 6 bedrooms 4 spaces, counting garage spaces, so converting a house to a duplex roughly doubles the requirement. The single-family row's maximum column also adds '2 additional for accessory structure', which is not explained elsewhere. Structures at least 50 years old are exempt from the minimum parking requirements (§157.046(E)(1)), which matters in Richmond's older neighborhoods.

Where a second unit is possible at all (a duplex in R-2, R-3 or a PUD), it is a permitted use: §157.041(A)(1) defines permitted uses as allowed outright without special conditions or review by anybody other than the Planning Commission, so the normal route is a building permit and zoning compliance rather than a Board of Adjustment hearing. Getting a duplex onto an R-1 lot instead requires a zoning map amendment (Planning Commission hearing and City Commission ordinance, §157.036(B)), which is a rezoning, not an ADU permit.

Duplex units may be rented long-term with no special license in the Development Ordinance. Short-term rentals (under 30 consecutive days) are permitted only in the R-1A, R-1B and R-1C zones and by conditional use permit in B-2, so a duplex unit in R-2 or R-3 cannot be used as a short-term rental. Each short-term rental must pass an inspection by planning or building staff and the fire marshal, register annually with the Planning and Zoning Department ($250 initial, $100 renewal), sit at least 500 ft from another short-term rental, and provide one on-site parking space per bedroom; a change of host or ownership voids the registration.