Reno's ADU Ordinance, Explained: What You Can Build and the Engineering It Needs

Reno homeowners can build backyard ADUs. The City Council adopted Ordinance No. 6727 on October 8, 2025 (Case TXT24-00002, Bill 7317), which added accessory dwelling unit standards to the Reno Municipal Code at §18.03.405 and allows an ADU in zones where single-family homes are permitted.

There's a lot of secondhand information floating around about what the ordinance did and didn't change. Here's what the adopted code actually says, and the structural engineering an ADU needs in Reno.

What Reno's ADU Ordinance Allows

RMC §18.03.405(a) sets the baseline rules:

• An ADU may be attached to and integrated with the principal single-family structure, or built as a detached accessory structure
• No more than one ADU per lot, and the minimum lot size is 5,000 square feet
• Maximum density standards don't apply to ADUs
• ADU height can't exceed the height of the existing primary residence
• One designated parking space must be provided on-site
• The ADU can't conflict with private restrictions under §18.01.305
• An attached ADU follows single-family residential design standards, takes its area maximum from Tables 3-6 and 3-7 by district — in SF-3, 1,600 square feet or 50 percent of the principal structure, whichever is less — and its front door can't be visible from the same street the main house's front door faces
• A detached ADU is a detached accessory structure, so the Tables 3-6 and 3-7 dimensional standards for your district govern it. On top of that, §18.03.405(a)(10) requires it to maintain a single-family image, stay subordinate to the principal dwelling in size, location, and appearance, and match its exterior finish, architectural features, and roof pitch

The same ordinance amended Table 3-5 so a lot can have one detached ADU or guest quarters in addition to the detached accessory structures normally allowed in every residential district — the ADU doesn't use up your shed or detached-garage allowance.

Reno didn't do this on its own timeline. Nevada Assembly Bill 396 (2025) requires counties of 100,000 or more and cities of 60,000 or more — Reno is named in the bill's digest — to adopt an ADU ordinance before July 1, 2026, or ADUs become authorized on any residentially zoned parcel without restriction.

Setbacks: Same as the Main House — Here's What That Means for Your Lot

§18.03.405(a)(8) is short: both attached and detached ADUs comply with the principal structure setback requirements. Your ADU gets no setback relief. Whatever front, side, and rear setbacks your zoning district puts on the house apply to the unit in the backyard.

If you've heard the city reduced ADU setbacks, it didn't. §18.03.405 has been amended twice since adoption — Ordinance No. 6732 (January 14, 2026) and Ordinance No. 6742 (June 3, 2026) — and neither touched the ADU provisions.

Practically, the setback is the first thing that decides whether a detached unit fits. Measure your buildable envelope before you design anything. Usable width is lot width minus the left and right side setbacks. Usable depth behind the house is lot depth minus the distance from the front lot line to the back wall of the house (measured, not the minimum front setback), minus the rear setback, minus the 3-foot separation Tables 3-6 and 3-7 require between detached structures on the same lot. Confirm your parcel's setbacks with the City of Reno, or send us your site plan and we'll tell you what fits.

What the Ordinance Rules Mean Structurally

Several of the zoning limits land directly on the structural design:

• Seismic. Reno sits in an active seismic region, so a detached ADU needs a complete lateral system and a continuous load path from roof to foundation, designed for the site's seismic and wind forces. Whether that ends up as braced wall panels, engineered shear walls with holdowns, or another system depends on the design forces and the code path. It isn't optional detailing on a small building.
• Snow and wind. Ground snow load in the Reno area varies sharply with elevation, and foothill parcels see meaningfully higher loads than the valley floor. Roof framing and the matching roof pitch the ordinance requires have to be designed for your site's actual load, not a generic number.
• Foundations. A detached ADU needs its own complete foundation sized for the site soil and frost depth. Backyard access, existing utilities, and neighboring footings all constrain how it gets built.
• Height matching the main house. Keeping the ADU under the primary residence's height can push a two-story unit into tight floor-to-floor dimensions, which affects framing depth and header sizing.
• Conversions. Turning a garage into an ADU means verifying the existing framing and foundation for the new loads — the most common source of surprises at plan review.

What the Permit Needs

Stamped structural plans go in with the building permit whenever the design falls outside the IRC prescriptive path. In practice that covers most detached ADUs in Reno — the seismic design category, snow load at elevation, and non-standard foundations push them past what the prescriptive tables can carry — plus any conversion that changes loads on the existing structure. A detached unit needs a complete foundation, framing, and lateral design. Garage conversions and above-garage units need the existing structure verified for the new loads. Our full guide covers each ADU type: ADU Structural Engineering: What Homeowners Need to Know.

We're headquartered in Reno — see what we build across our home market on the Reno structural engineering page — and we work with the City of Reno building department every week.

Reno ADU Ordinance — FAQ