11-810.01. Accessory dwelling units; regulation; applicability; definitions

A. A county shall adopt regulations that allow both of the following on any lot or parcel where a single-family dwelling is allowed:

1. At least one attached and one detached accessory dwelling unit as a permitted use.

2. A minimum of one additional detached accessory dwelling unit as a permitted use on a lot or parcel that is one acre or more in size. The county may require at least one accessory dwelling unit on the lot or parcel to be a restricted-affordable dwelling unit.

B. A county shall allow each accessory dwelling unit developed pursuant to this section to be at least seventy-five percent of the gross floor area of the single-family dwelling on the same lot or parcel or one thousand square feet, whichever is less. This subsection does not prohibit a county from allowing an accessory dwelling unit that is larger than the size of an accessory dwelling unit that is allowed pursuant to this subsection.

C. A county may not do any of the following:

1. Prohibit the use or advertisement of either the single-family dwelling or any accessory dwelling unit located on the same lot or parcel as separately leased long-term rental housing.

2. Require a familial, marital, employment or other preexisting relationship between the owner or occupant of a single-family dwelling and the occupant of an accessory dwelling unit located on the same lot or parcel.

3. Require that a lot or parcel have additional parking to accommodate an accessory dwelling unit or require payment of fees instead of additional parking.

4. Require that an accessory dwelling unit match the exterior design, roof pitch or finishing materials of the single-family dwelling that is located on the same lot as the accessory dwelling unit.

5. Set restrictions for accessory dwelling units that are more restrictive than those for single-family dwellings within the same zoning area with regard to height, setbacks, lot size or coverage or building frontage.

6. Set rear or side setbacks for accessory dwelling units that are more than five feet from the property line.

7. Require improvements to public streets as a condition of allowing an accessory dwelling unit, except as necessary to reconstruct or repair a public street that is disturbed as a result of the construction of the accessory dwelling unit.

8. Except as provided in subsection A, paragraph 2 of this section, require a restrictive covenant concerning an accessory dwelling unit on a lot or parcel zoned for residential use by a single-family dwelling.

D. This section does not prohibit restrictive covenants or shared well agreements as provided by state law concerning accessory dwelling units entered into between private parties. The county may not condition a permit or license or the use of an accessory dwelling unit on adopting or implementing a restrictive covenant between private parties.

E. This section does not supersede applicable building codes, fire codes, sensitive environmental area regulations, wildfire prevention regulations, emergency vehicle access regulations, drainage and flood control regulations or public health and safety regulations, except that a county may not require an accessory dwelling unit to comply with a commercial building code or contain a fire sprinkler.

F. An accessory dwelling unit may not be built on top of a current or planned public utility easement unless the property owner receives written consent from any utility that is currently using the public utility easement or that may use the public utility easement in the future.

G. If a county fails to adopt development regulations as required by this section on or before January 1, 2026, accessory dwelling units shall be allowed on all lots or parcels zoned for residential use in the county without limits.

H. This section does not apply to lots or parcels that are located on:

1. Tribal land.

2. Land that is in the territory in the vicinity of a military airport or ancillary military facility or property that is in a high noise or accident potential zone as defined in section 28-8461.

3. Land that is in the territory in the vicinity of a federal aviation administration commercially licensed airport or a general aviation airport or land that is in the territory in the vicinity of a public airport as defined in section 28-8486 and that has a noise level of greater than sixty-five decibels.

I. If a new accessory dwelling unit will not be connected to a sewer system or if the sewer system lacks capacity to serve the new accessory dwelling unit, a county may require that any septic system that will be used to serve the accessory dwelling unit be adequately sized before the construction of the accessory dwelling unit.

J. For the purposes of this section:

1. "Accessory dwelling unit" means a self-contained living unit that is on the same lot or parcel as a single-family dwelling of greater square footage than the accessory dwelling unit, that includes its own sleeping and sanitation facilities and that may include its own kitchen facilities.

2. "Gross floor area" means the interior habitable area of a single-family dwelling or an accessory dwelling unit.

3. "Long-term rental" means rental use in which the tenant holds a lease of ninety days or longer or on a month-by-month basis.

4. "Permitted use" means the ability for a development to be approved without requiring a public hearing, variance, conditional use permit, special permit or special exception, other than a discretionary zoning action to determine that a site plan conforms with applicable zoning regulations.

5. "Restricted-affordable dwelling unit" means a dwelling unit that, either through a deed restriction or a development agreement with the county, is rented to households earning up to eighty percent of the area median income.