The Complete ADU Guide for Sacramento Homeowners
Everything you need to know about building an Accessory Dwelling Unit in Sacramento from feasibility and permits to construction and move-in. Step-by-step costs, timelines, and local contractor recommendations.
Timeline Overview
Your ADU Roadmap From First Sketch to Final Inspection
A Sacramento ADU usually moves through four clear phases: planning, permit review, construction, and final closeout. Use this roadmap to see where money, time, and contractor coordination typically land.
- Typical timeline
-
6-12 mo
Design to move-in
- Working budget
-
$80K $250K
Common Sacramento range
- Permit review
-
60 days
For complete ADU applications
Relative effort varies by site access, utilities, plan-check comments, and contractor availability.
- 1
Plan
Research & Feasibility
Confirm lot fit, ADU type, access, utilities, and early budget before paying for drawings.
1-2 weeks
$0-$500
- 2
Plan
Design & Plans
Turn the concept into site plans, floor plans, elevations, engineering, and Title 24 documents.
4-8 weeks
$5,000-$15,000
- 3
Permit
Permits & Approvals
Submit the package, answer plan check comments, and clear local building department review.
4-8 weeks
$2,000-$15,000
- 4
Build
Site Preparation
Prepare access, protect the property, handle demo, grading, trenching, and temporary controls.
1-2 weeks
$2,000-$10,000
- 5
Build
Foundation
Set footings, slab or raised foundation details, and underground utility paths correctly.
2-4 weeks
$7,000-$25,000
- 6
Build
Framing & Structure
Build the shell: walls, roof, openings, sheathing, weatherproofing, and structural inspections.
2-4 weeks
$15,000-$40,000
- 7
Build
Mechanical Systems
Coordinate plumbing, electrical, HVAC, fire safety, and rough inspections before walls close.
2-4 weeks
$15,000-$35,000
- 8
Build
Interior Finishes
Drywall, cabinets, flooring, tile, paint, fixtures, appliances, and punch-list quality control.
3-6 weeks
$15,000-$40,000
- 9
Finish
Exterior & Landscaping
Finish paths, drainage, fencing, lighting, address visibility, and private outdoor space.
1-3 weeks
$3,000-$15,000
- 10
Finish
Final Inspections & Move-in
Clear final inspections, collect closeout documents, and get the unit ready for occupancy.
1-2 weeks
$500-$2,000
By Jurisdiction
Which Sacramento-area city is easiest for an ADU right now?
The biggest swing in your ADU timeline isn't the build it's the jurisdiction. Several Sacramento-area cities now offer pre-approved or permit-ready plan sets that skip much of the design-review back-and-forth. Local rules shift year to year, so confirm the current program with your city before you bank on it, but here's the 2026 lay of the land.
Offers free permit-ready ADU plan sets to cut design cost and review time. See the full city-by-city comparison →
DavisBuilding-permit-only path vs. pre-designed plans which fits your lot and budget →
Elk GroveShelf-ready / pre-approved plans and when the fast path actually saves money →
Budget reality checkWhat a backyard cottage really costs once utilities, fees, and site work are in →
Research & Feasibility
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.
Next step: Get a free initial consultation with a licensed general contractor to assess your property. Find General Building contractors in Sacramento →
Design & Plans
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.
Find a design-build contractor: General Building contractors in Sacramento →
Permits & Approvals
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.
Important: Only work with CSLB-licensed contractors. California law requires a CSLB-licensed contractor for any project that needs a building permit or totals $1,000 or more in combined labor and materials (homeowners can do smaller, no-permit jobs themselves).
Site Preparation
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.
Find contractors: Earthwork & demolition contractors in Sacramento →
Foundation
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
Framing & Structure
- Wood framing: $15,000-$35,000
- Prefab/modular panels: $20,000-$40,000
- Roofing: $5,000-$15,000
Sacramento Roofing Contractors
Mechanical Systems
- 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
Pro-plumbing Inc
CSLB Licensed · Sacramento
Always Affordable Plumbing & HVAC
CSLB Licensed · Sacramento
Go Pro Plumbing Heating & Air
CSLB Licensed · Sacramento
Electrical Contractors
V3 Electric Inc
CSLB Licensed · Sacramento
Eisenbeisz Electric
CSLB Licensed · Sacramento
A A A Electrical Solutions
CSLB Licensed · Sacramento
HVAC Contractors
Interior Finishes
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
Find specialists: Flooring → · Painting → · Drywall →
Exterior & Landscaping
- Siding (to match main house): $3,000-$10,000
- Landscaping restoration: $2,000-$8,000
- Walkway/driveway: $1,000-$5,000
Final Inspections & Move-in
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.
Cost Summary
Total ADU Cost Breakdown
| Phase | Timeline | Cost Range |
|---|---|---|
| 1. Research & Feasibility | 1-2 weeks | $0-$500 |
| 2. Design & Plans | 4-8 weeks | $5,000-$15,000 |
| 3. Permits & Approvals | 4-8 weeks | $2,000-$15,000 |
| 4. Site Preparation | 1-2 weeks | $2,000-$10,000 |
| 5. Foundation | 2-4 weeks | $7,000-$25,000 |
| 6. Framing & Structure | 2-4 weeks | $15,000-$40,000 |
| 7. Mechanical Systems | 2-4 weeks | $15,000-$35,000 |
| 8. Interior Finishes | 3-6 weeks | $15,000-$40,000 |
| 9. Exterior & Landscaping | 1-3 weeks | $3,000-$15,000 |
| 10. Final Inspections & Move-in | 1-2 weeks | $500-$2,000 |
| Detached New Build Total | 6-12 months | $80,000-$250,000 |
| Garage Conversion Total | 3-6 months | $50,000-$150,000 |
* Costs are estimates based on Sacramento-area averages reviewed for 2026. Actual costs vary by project scope, materials, and market conditions. Always get multiple quotes from licensed contractors.
Regulations
Important California ADU Laws
AB 1033 (2023) Sell Your ADU Separately
Allows ADUs to be sold separately as condominiums, if the local jurisdiction opts in. This opens the door to ADU homeownership without purchasing the entire property. Read the bill →
AB 976 (2023) No Owner-Occupancy Required
Permanently removed owner-occupancy requirements for ADUs. You can rent out both your primary home and your ADU. Read the bill →
SB 477 (2024) Government Code Reorganization
Renumbered and reorganized ADU-related Government Code sections for clarity. No substantive policy changes. Read the bill →
Additional Key Rules
- • HOAs cannot ban ADUs but can impose reasonable design restrictions that don't unreasonably increase cost or effectively prohibit construction.
- • No parking required for ADUs within ½ mile of public transit, in historic districts, or when on-street parking permits are available to residents.
- • No fire sprinklers required if the primary dwelling doesn't have them.
Frequently Asked Questions
ADU FAQ
How much does it cost to build an ADU in Sacramento?
How long does it take to build an ADU in Sacramento?
Do I need a permit to build an ADU in Sacramento?
What is the maximum size for an ADU in California?
Can I sell my ADU separately from my main house?
Do I have to live on the property if I build an ADU?
Can my HOA prevent me from building an ADU?
Do I need to provide parking for my ADU?
Ready to Build Your ADU?
Find licensed, CSLB-verified contractors in Sacramento who specialize in ADU construction.
Find ADU Contractors →Disclaimer: Costs are estimates based on Sacramento-area averages reviewed for 2026. Actual costs vary significantly based on project scope, site conditions, materials, and labor market conditions. Always obtain multiple quotes from licensed contractors. Regulatory information is provided for general guidance only and may change verify current requirements with the City of Sacramento and the CSLB. Sacramento Valley Contractors is a directory service and does not provide construction, legal, or financial advice. See our full disclaimer.