ADU rules in Sarpy County

The Sarpy County Zoning Regulations have no accessory dwelling unit use. A second detached house is allowed by right only through Section 1.7.2, which lets more than one single-family residence stand on one lot if the lot could be split into separate lots that each fully conform, so the lot must hold at least twice the district minimum (2 acres in RE1, 4 acres in RE2, 10 acres in AGR, 20,000 sq ft in RS-100, 14,400 sq ft in RS-72). In AG and AGD, farm dwellings for the owner's family, tenants and employees are a principal permitted use. A detached guest house is allowed only without a kitchen and may not be rented or used as a separate dwelling unit, so it is not an ADU.

The regulations have no accessory dwelling use, and the only route to a second unit inside or attached to a house is a two-family dwelling, which is a permitted use only in RD-50 and the RG districts (10,000 sq ft minimum lot for a two-family dwelling). It is not allowed in the AG, AGD, AGR, RE or RS districts, which cover most unincorporated single-family land. A single-family dwelling is defined as having kitchen and toilet facilities for only one family, so adding a second kitchen unit on an ordinary single-family lot is not allowed.

Because there is no ADU use, there is no ADU floor-area cap. A second residence under §1.7.2 is a full single-family dwelling held to the district's dwelling standards: 35 feet maximum height in every agricultural and residential district and the lot-area, width and yard minimums for each would-be lot. All buildings on a residential lot may cover at most 40 percent of it (75 percent in other districts). The §3.3.4 cap on accessory buildings (1.5 times the principal structure's footprint outside AG and AGD) and the 720 sq ft garage limit in the RS, RD, RG and RMH districts apply to accessory buildings such as a no-kitchen guest house, not to a second dwelling.

Nothing in the regulations requires the owner to live on a lot with two residences. Section 1.7.2 sets only the subdividability test, and the AG and AGD farm-dwelling use expressly includes dwellings for tenants and employees.

The parking table requires two spaces per dwelling unit for residential uses, so a second residence brings its own two spaces. The requirement applies at construction, alteration or change of use.

A second residence that meets §1.7.2 or a farm dwelling in AG or AGD is a principal permitted use, so the route is a county building permit after the Director of Planning's zoning compliance review of a site plan, with no hearing. Dwellings need a building permit even on exempt farmsteads. Nothing in the regulations offers a special use permit for an accessory dwelling, so a lot that fails the subdividability test has no discretionary route short of rezoning or a variance.

The regulations put no rental limit on a second single-family residence or a farm dwelling for tenants. A guest house (no kitchen) is defined as for temporary guests and "not rented", and servants' quarters, although they may have a kitchen, are also "not rented" and are not listed as a use in any district. The regulations contain no short-term rental, vacation rental or bed-and-breakfast provision; Neb. Rev. Stat. 18-1758 binds cities and villages, not counties.