What are setbacks for an ADU?

Setbacks are the minimum distances your ADU must be from property lines and sometimes from the primary house. They shape the ‘buildable box’ on your lot. Exact numbers vary by city and zone. {{verify locally}}

Do I need a new off-street parking space?

Some places require one space per ADU, while many waive parking if the ADU is within a set distance of transit, in a historic district, or inside an existing structure (like a garage conversion). Always confirm the current exemptions. {{verify locally}}

How tall can my ADU be?

Typical ranges are roughly one-story (16–20 ft) and two-story (24–28 ft), but your limit can be lower or higher based on roof type, lot width, and adjacency to an alley. Check your code for eave height vs ridge height. {{verify locally}}

What if my lot is odd-shaped or slopes?

Irregular lots, flag lots, slopes, and easements can shrink the buildable area or move setback lines. Planning staff can confirm how your lot geometry applies. {{verify locally}}

Are garage conversions treated differently?

Conversion ADUs often keep the existing garage footprint and may be exempt from current setbacks, but must meet building safety codes and may have height/roofline caveats. {{verify locally}}

Modern backyard ADU with landscaped path and warm evening light

Regulations

Setbacks, Parking & Height for ADUs (2025)

Learn the three rules that shape where your ADU fits—without getting lost in code sections.

Check your local rules Compare builder options Get matched with vetted builders

Quick Table of Contents

Setbacks, parking, and height determine where your ADU can go and how big it can be. Start by finding your zoning code and any overlays, then confirm the ADU chapter for exact numbers. Rules vary by city—treat examples below as guides and {{verify locally}} with your planning portal.

What are setbacks?

Setbacks are minimum distances from your property lines (and sometimes the main house). They form a “buildable box.” Corner lots, alleys, and easements can change which edge counts as “rear.” {{verify locally}}

Condition	Illustrative range	Notes
Side yard	3–5 ft	Fire separation & eaves can matter; trees/utilities may add buffers. {{verify locally}}
Rear yard	4–10 ft	Lots with alleys often allow slightly different rear setbacks. {{verify locally}}
Front yard	Usually not in front setback	Front yard ADUs are less common and often restricted. {{verify locally}}
Garage conversion	Existing footprint	Conversions frequently keep current location, subject to safety codes. {{verify locally}}

Numbers are illustrative; always confirm with your city/county code or state ADU handbook. {{verify locally}}

Sketch your “buildable box”

Print a parcel map or trace your lot outline.
Inset the setback distances from each property line.
Mark easements, large trees, and utility lines.
That inner shape is your starting box for the ADU footprint.

Parking rules (and common exemptions)

Some jurisdictions require one off-street space per ADU; others waive parking if you’re near transit, in a historic district, or if the ADU is created inside an existing structure (like a garage). Always confirm current exemptions and definitions of “near transit.” {{verify locally}}

Transit proximity: Waivers often apply within a set distance of a bus/rail stop. {{verify locally}}
Existing structure: Conversions frequently exempt parking because no new building area is added. {{verify locally}}
Street parking: Some cities allow it to count; many do not. {{verify locally}}

Tip: Avoid “surprise” parking conditions

Check if your street has Residential Parking Permits, seasonal snow rules, or curb cuts required for driveways—these can affect feasibility. {{verify locally}}

Height limits (one vs two stories)

Height is usually measured to the average roof midpoint or ridge, with separate limits on eave height. Expect one-story caps ~16–20 ft and two-story caps ~24–28 ft, with design rules near property lines. {{verify locally}}

Chart is illustrative only. Always confirm measurement method (ridge vs midpoint) and eave height. {{verify locally}}

How to check your parcel (5 steps)

Find your zoning. Use your city/county planning portal; note base zone + overlays. {{verify locally}}
Open the ADU chapter. List max size, height, and each setback. {{verify locally}}
Check parking. Record if required and any exemptions (transit, conversion). {{verify locally}}
Map constraints. Draw easements, slopes, trees; adjust your buildable box.
Confirm with staff. Email planning a simple sketch and questions; save replies for your permit file.

Open state & city rules Ask for a quick feasibility check

FAQ

Do alleys change setbacks?

Often, yes—lots with alleys can use reduced rear setbacks or alternate height transitions. {{verify locally}}

Can my ADU be in front of the main house?

Front-yard ADUs are less common and more regulated. Some cities allow courtyard placement with design standards. {{verify locally}}

What if my eaves cross into a setback?

Many codes allow limited eave or gutter encroachments (e.g., 12–24"). Fire separation may change this. {{verify locally}}

Do sprinklers affect height or size?

Sprinklers are a building code/safety question rather than zoning, but required systems can influence feasible layouts and costs. {{verify locally}}

Is a second story worth it?

Two stories add stairs and structure costs but reduce footprint impacts. Builders can price both options; compare against setback constraints and privacy. {{verify locally}}

Next steps

Open your state/city page in Regulations and confirm the exact numbers. {{verify locally}}
Sketch your buildable box and decide one-story vs two-story.
Ask for pricing from a prefab and a custom builder via the RFQ form.