The Complete ADU Guide for Sacramento Homeowners

Before spending any money, determine what type of ADU is right for your property and budget. There are four main types:

• Detached new build — A standalone structure in your backyard. Most flexible design, highest cost.
• Garage conversion — Converting an existing garage into living space. Lower cost, faster timeline.
• Attached addition — An extension added to your existing home.
• Junior ADU (JADU) — Under 500 sq ft, carved out of existing living space (e.g., converting a bedroom with a separate entrance and kitchenette).

California ADU Size Limits

• Detached ADU: Up to 1,200 sq ft
• Attached ADU: Up to 50% of existing home's living area
• JADU: Up to 500 sq ft

Sacramento Zoning & Setbacks

Under California state law, all residential zones in Sacramento allow ADUs. There is no minimum lot size requirement. Key setback rules:

• 4 ft from side and rear lot lines for new construction
• 0 ft setback for garage conversions (existing footprint)

Start with the Sacramento ADU Resource Center to check property-specific requirements.

You have two main paths for ADU plans:

Pre-Approved Plans ($0–$3,000)

Sacramento offers a pre-approved ADU plan program that significantly speeds up permitting. These plans have already been reviewed for building code compliance. Check the City of Sacramento ADU page for available pre-approved plans.

Custom Architectural Plans ($5,000–$15,000)

For a custom design, you'll work with an architect or design-build contractor. Cost depends on size and complexity. Your plans must include:

• Floor plan and elevations
• Site plan showing ADU placement on your lot
• Structural engineering calculations
• Title 24 energy compliance calculations

Many general contractors offer design-build services, handling both the design and construction under one contract.

Sacramento processes ADU permits ministerially—meaning no discretionary review and no public hearing is required. California law mandates that cities approve or deny complete ADU applications within 60 days.

Permit Fees

• Building permit fees vary by project value
• ADUs under 750 sq ft: No impact fees (California law)
• ADUs 750+ sq ft: Impact fees must be proportional to size
• School fees may apply (~$4.79/sq ft for unified school districts—verify current rate with your district)

Typical permit timeline in Sacramento is 4–8 weeks for complete applications.

Once permits are approved, site work begins:

• Demolition (if garage conversion): $3,000–$8,000
• Grading and excavation: $2,000–$10,000
• Tree removal (if needed): $500–$3,000 per tree. Note: Sacramento has a tree preservation ordinance—check requirements before removing any trees.

The foundation type depends on your ADU design and site conditions:

• Concrete slab-on-grade (most common in Sacramento): $7,000–$15,000
• Raised foundation: $12,000–$25,000
• Garage conversion foundation reinforcement: $5,000–$15,000

Sacramento Concrete Contractors

• Wood framing: $15,000–$35,000
• Prefab/modular panels: $20,000–$40,000
• Roofing: $5,000–$15,000

Sacramento Roofing Contractors

• Plumbing (rough-in and finish): $5,000–$15,000
• Electrical (wiring and panel): $5,000–$12,000
• HVAC (mini-split most common for ADUs): $3,000–$8,000

Sacramento's hot summers (regularly exceeding 100°F) make proper HVAC essential. Ductless mini-split systems are the most popular choice for ADUs—they're efficient, compact, and provide both heating and cooling.

Plumbing Contractors

Electrical Contractors

HVAC Contractors

This is where your ADU starts to feel like a home:

• Drywall: $3,000–$8,000
• Flooring: $3,000–$10,000
• Kitchen (if full kitchen): $5,000–$20,000
• Bathroom: $5,000–$15,000
• Paint: $2,000–$5,000

• Siding (to match main house): $3,000–$10,000
• Landscaping restoration: $2,000–$8,000
• Walkway/driveway: $1,000–$5,000

The final stretch:

• Final building inspection — The city inspector verifies all work meets code.
• Utility connections and meter setup — Separate meters for water, electric, and gas (if applicable).
• Certificate of Occupancy — Once issued, the ADU is legally habitable.