5 county-level rules, plus city-specific rules for 1 city in Washoe County, Nevada.
Verified from official government sources
In unincorporated Washoe County, one ADU is allowed per parcel. Attached ADUs need a 5,000 sq ft lot; detached need 12,000 sq ft. Detached units are capped at 1,500 sq ft (800 in Medium Density Suburban).
WCC 110.306.25(d)
The detached accessory dwelling unit shall not exceed fifteen hundred (1,500) square feet, or fifty (50) percent of the total square footage of the main dwelling unit, whichever is smaller. In the Medium Density Suburban (MDS) Regulatory Zone, the detached accessory dwelling unit shall not exceed eight hundred (800) square feet.
Detached sheds and accessory structures 12 feet or less in height may sit within required rear and side setbacks if kept at least 5 feet from those property lines. They are never allowed in the front yard setback.
WCC 110.306.10(b)(1)
Accessory structures 12 feet in height or less may be located within the required rear and side yard setbacks provided they are five feet or more from the rear and side property line. Accessory structures are prohibited within the required front yard setback.
Converting a garage or accessory structure into livable space turns it into a dwelling unit subject to the county's ADU rules. Installing both a kitchen and a toilet automatically makes it a dwelling unit.
WCC 110.306.10(h)
Installation of both a kitchen (as defined in Article 902) and a toilet in a detached accessory structure shall render the structure as a dwelling unit subject to the provisions of this article.
Carports and private garages are detached accessory structures under WCC 110.306.10. A private garage on a steep-sloped interior lot may be built to the property line if under 15 feet interior height and Engineering finds no safety or snow-removal conflict.
WCC 110.306.10(e)
A detached accessory structure used as a private garage on any interior lot where the slope of the front half of the lot is greater than a two foot rise (or fall) for every ten feet... may be built to the property line, provided such structure shall not exceed 15 feet in interior height when measured from parking surface.
A manufactured or modular home built within 6 years of placement may serve as a detached ADU if permanently affixed and converted to real property. A shed or accessory structure cannot be a mobile/manufactured home.
WCC 110.306.25(e)
A manufactured or modular home constructed within six (6) years of the date of its placement is permitted as a detached accessory dwelling unit, subject to the size and regulatory zone requirements in (d) above and the provisions of Article 312, Fabricated Housing, provided that the unit is permanently affixed to the property.
1 cities in Washoe County have their own accessory structures rules. Each link goes to that city's dedicated page with code citations.
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