The Reno ADU landscape has transformed dramatically since the City Council adopted its landmark ordinance in October 2025. As we move through 2026, homeowners across Washoe County are discovering that building an Accessory Dwelling Unit involves navigating a complex web of local, regional, and state requirements.
This guide consolidates everything we've learned from dozens of ADU projects across Reno, Sparks, and unincorporated Washoe County. Whether you're planning a garage conversion in Old Southwest or a detached casita in Northwest Reno, this is your roadmap to getting permitted.
Understanding Jurisdiction: City of Reno vs. Washoe County
The first question every ADU hopeful must answer is: who has authority over my property? This determines which regulations apply and which office processes your permit.
City of Reno: If your property lies within Reno city limits, you'll work with the City of Reno Community Development Department. The city uses the OneNV regional permitting portal for all applications.
City of Sparks: Properties in Sparks follow that city's ADU ordinance, which closely mirrors Reno's but has some distinct requirements. Sparks also uses OneNV.
Unincorporated Washoe County: If you're outside city limits, such as in parts of Cold Springs, Lemmon Valley, or the South Valleys, Washoe County Building and Safety handles your permits. The county has its own ADU regulations that differ in some respects from the cities.
To determine your jurisdiction, check your property tax bill or search the Washoe County Assessor's website. The jurisdiction is listed on your parcel information.
The 5,000 Square Foot Rule and Its Exceptions
Reno's ADU ordinance established a 5,000 square foot minimum lot size for detached ADUs. This threshold was a hard-fought compromise, as earlier proposals suggested 9,000 square feet, which would have excluded most of the city's established neighborhoods.
However, the 5,000 square foot rule isn't absolute. Here's what we've learned about exceptions and edge cases:
Garage Conversions: If you're converting an existing garage to living space (not building new), some flexibility exists for lots slightly under 5,000 square feet. The city evaluates these on a case-by-case basis, considering factors like parking availability and neighborhood impact.
Corner Lots: Properties on corner lots may have different setback calculations that effectively reduce the buildable area. We've seen projects on 5,200 square foot corner lots struggle to fit an ADU while meeting all setback requirements.
Easements: Utility easements, drainage easements, and access easements reduce your effective lot size. A property that appears to be 5,500 square feet might have only 4,800 square feet of buildable area once easements are excluded.
The Permit Application Process: Step by Step
Based on our experience with the City of Reno, here's the realistic timeline and process for ADU permits:
Step 1: Pre-Application Meeting (Optional but Recommended) The City of Reno offers pre-application meetings where you can discuss your project with planning staff before submitting formal plans. This $150 meeting can save thousands in revision costs by identifying issues early.
Step 2: Prepare Your Submittal Package Your application must include:
- Site plan showing the ADU location, setbacks, and parking
- Floor plans and elevations
- Structural calculations (stamped by a Nevada-licensed engineer)
- Energy compliance documentation (Title 24 equivalent)
- Utility connection plan
Step 3: Submit Through OneNV Create an account at onenv.us and submit your application electronically. The system will generate a project number you'll use for all future correspondence.
Step 4: Plan Review (4-8 Weeks) City staff review your plans for compliance with building codes, zoning requirements, and design standards. Expect at least one round of corrections. The most common issues we see:
- Insufficient setback documentation
- Missing structural details at beam connections
- Incomplete electrical load calculations
Step 5: Permit Issuance Once approved, you'll pay permit fees and receive your building permit. Only then can construction begin.
Step 6: Inspections During construction, you'll need inspections at key milestones:
- Foundation/slab before concrete pour
- Rough framing
- Rough electrical, plumbing, and mechanical
- Insulation
- Final inspection
The Real Cost of Permits and Fees
Permit fees are just the beginning. Here's the complete picture of what you'll pay before construction starts:
Building Permit Fee: Calculated based on project valuation. For a $200,000 ADU, expect approximately $2,500-$3,500.
Plan Review Fee: Typically 65% of the building permit fee, so $1,625-$2,275 for our example.
Regional Road Impact Fee (RRIF): Currently $3,742 for a new residential unit in Reno.
Parks and Police Impact Fees: Combined approximately $1,150.
Sewer Connection Fee: This is often the biggest surprise. The City of Reno charges $8,700-$13,200 for connecting a new dwelling unit to the municipal sewer system. The exact amount depends on your location within the service area.
Water Connection: If you need a separate water meter (required for some rental situations), TMWA charges connection fees plus the cost of the meter and installation. Budget $3,000-$5,000.
Total Pre-Construction Costs: For a typical detached ADU in Reno, expect $20,000-$28,000 in permits, fees, and utility connections before you break ground.
Design Standards: The "Architecture Matching" Requirement
Reno's ADU ordinance includes specific design standards intended to preserve neighborhood character. These aren't suggestions; they're enforceable requirements that will be checked during plan review.
Height Limitation: Your ADU cannot exceed the height of your primary residence. If you have a single-story home, your ADU must be single-story. This is measured to the highest point of the roof.
Roof Pitch: The ADU's roof pitch must match the primary residence within 15%. If your home has a 4:12 pitch, your ADU should be between 3.4:12 and 4.6:12.
Exterior Materials: Siding, trim, and roofing materials must be "compatible" with the main house. This doesn't mean identical, but the city expects visual harmony.
Placement: Detached ADUs must be located in the rear yard, behind the rear building line of the primary residence. Front yard ADUs are prohibited.
Parking Requirements: The One-Space Rule
Every ADU in Reno requires one dedicated off-street parking space. This space must be:
- Located on your property (not on the street)
- Outside the front yard setback
- Accessible without moving another vehicle (tandem parking doesn't count)
For properties with alley access, this requirement is often easy to meet. For properties without alleys, especially in neighborhoods like Old Southwest where lots are narrow, parking can be the project's biggest design challenge.
Short-Term Rental Considerations
As of early 2026, Reno allows ADUs to be used as short-term rentals (Airbnb, VRBO, etc.). However, the City Council has indicated they may revisit STR regulations later this year.
If rental income is part of your ADU strategy, we recommend:
- Building a unit that works for both short-term and long-term tenants
- Following the city's STR registration requirements
- Staying informed about potential regulatory changes
Common Mistakes That Delay Permits
Based on our experience, here are the issues that most frequently cause permit delays:
Incomplete Applications: Missing documents or incomplete forms get your application sent back before review even begins. Double-check the submittal checklist.
Setback Errors: Miscalculating setbacks is surprisingly common. Remember that setbacks are measured from property lines, not fences or perceived boundaries.
Utility Coordination: Failing to coordinate with TMWA and NV Energy early can add months to your timeline. Start these conversations during design, not after permit approval.
Structural Under-Engineering: The city's plan reviewers are thorough. Structural calculations that work "in theory" but lack specific connection details will be rejected.
Working with Avail Enterprises
Navigating the ADU permit process doesn't have to be overwhelming. At Avail Enterprises, we've guided dozens of Reno homeowners through this exact process. We handle permit applications, coordinate with utilities, and ensure your project meets all requirements before you invest in construction.
Schedule a free ADU consultation [blocked] to discuss your property's potential. We'll review your lot, explain the applicable regulations, and provide a realistic timeline and budget for your project.