ADU Cost Guide Sacramento 2026

Building an ADU in Sacramento is one of the smartest investments a homeowner can make right now. Rental income, multigenerational living, increased property value — the upside is real. But before you break ground, you need to know what it actually costs.

This guide gives you real numbers, not vague ranges. We've worked on over 1,000 residential projects across Greater Sacramento, and we're sharing exactly what you can expect to spend in 2026.

The Three Cost Buckets Every ADU Owner Needs to Understand

Every ADU project has three distinct cost categories. Confusing them — or leaving one out — is how homeowners end up with budget surprises mid-project.

1. Design & Plans — architectural drawings, structural calculations, and permit-ready plan sets
2. Permits & Fees — city and county fees, school fees, utility connections
3. Construction — the actual build

Most online cost guides only talk about construction. We're going to cover all three.

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1. Design & Plans: What You'll Pay for Permit-Ready Drawings

Your permit-ready plan set is the foundation of your entire project. Without it, you can't pull a permit. Without a permit, you can't legally build — or sell.

Typical design fees for ADUs in Sacramento (2026):

ADU Type	Square Footage	Design Fee Range
Detached ADU	400–600 sq ft	$720 – $1,080
Detached ADU	600–1,000 sq ft	$1,080 – $1,800
Garage Conversion (JADU)	400–600 sq ft	$520 – $780
Attached ADU	500–800 sq ft	$900 – $1,440

At Liberty Drafting Studios, we charge $1.80 per square foot for ADU plan sets, with a typical turnaround of 10–15 business days. That includes full construction documents, structural details, and everything your building department needs for plan check.

What's included in a complete ADU plan set:

• Site plan and floor plan
• Elevations (all four sides)
• Sections and details
• Electrical, mechanical, and plumbing layouts
• Title 24 energy compliance
• Structural calculations (when required)

What's NOT included: Soils reports, survey work, or Title 24 energy calculations performed by a third-party consultant. These are rare for standard ADUs but may be required on certain lots.

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2. Permits & Fees: The Costs Most Homeowners Forget

Permit fees in Sacramento County and the City of Sacramento have changed significantly since AB 68 and SB 13 passed. Here's what you're looking at in 2026.

City of Sacramento ADU permit fees (approximate):

• Building permit: $2,500 – $5,000 (based on valuation)
• Plan check fee: $800 – $1,500
• School fees: Waived for ADUs under 500 sq ft; $3.79/sq ft for larger units
• Utility connection fees: $3,000 – $8,000 (varies by utility district)

Sacramento County (unincorporated areas):

Fees are similar but vary by jurisdiction. Elk Grove, Roseville, Folsom, and Rancho Cordova each have their own fee schedules. We coordinate permits across all of these jurisdictions regularly.

Total permit cost range: $6,000 – $15,000 depending on size, location, and utility requirements.

Pro tip: ADUs under 500 square feet are exempt from school fees under California law. If you're on the fence between 499 and 520 square feet, the math often favors staying under 500.

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3. Construction Costs: The Biggest Variable

Construction is where costs vary the most — and where the most surprises happen. Here are realistic 2026 numbers for Greater Sacramento.

Cost per square foot by ADU type:

ADU Type	Low End	Mid Range	High End
Garage Conversion	$80 – $120/sq ft	$130 – $160/sq ft	$170 – $220/sq ft
Detached ADU (standard)	$200 – $250/sq ft	$260 – $320/sq ft	$330 – $400/sq ft
Attached ADU	$180 – $230/sq ft	$240 – $290/sq ft	$300 – $380/sq ft
Prefab/Modular ADU	$150 – $200/sq ft	$210 – $260/sq ft	$270 – $340/sq ft

What drives costs up:

• Hillside or difficult lot access
• Existing foundation issues
• High-end finishes (custom cabinetry, tile, fixtures)
• Separate utility meters
• HVAC systems (mini-splits are the most cost-effective option)

What keeps costs down:

• Garage conversions (existing structure, no foundation work)
• Simple rectangular footprint
• Standard finishes
• Shared utilities with main house

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Total ADU Cost: Putting It All Together

Here's a realistic all-in budget for three common ADU scenarios in Sacramento:

Scenario 1: Garage Conversion to JADU (500 sq ft)

• Design & plans: $900
• Permits & fees: $6,500
• Construction: $55,000 – $80,000
• Total: $62,000 – $87,000

Scenario 2: Detached ADU (600 sq ft)

• Design & plans: $1,080
• Permits & fees: $9,000
• Construction: $156,000 – $192,000
• Total: $166,000 – $202,000

Scenario 3: Attached ADU (800 sq ft)

• Design & plans: $1,440
• Permits & fees: $10,500
• Construction: $192,000 – $232,000
• Total: $204,000 – $244,000

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How Long Does an ADU Take in Sacramento?

Timeline matters as much as cost. Here's a realistic schedule:

1. Design & plan preparation: 10–15 business days (with Liberty Drafting Studios)
2. Plan check (city review): 4–12 weeks depending on jurisdiction and backlog
3. Correction responses: 1–3 weeks if corrections are required
4. Permit issuance: 1–2 weeks after approval
5. Construction: 3–6 months for detached ADU; 6–10 weeks for garage conversion

Total timeline from first call to move-in: 6–12 months is realistic. Projects with experienced teams and clean plan sets move faster.

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What California Law Says About ADU Fees (And How It Protects You)

California's ADU laws — AB 68, SB 13, AB 3182, and AB 2221 — have significantly reduced the barriers to building ADUs. Key protections for Sacramento homeowners:

• No impact fees for ADUs under 750 sq ft
• No owner-occupancy requirement (you don't have to live on the property)
• Ministerial approval — cities cannot deny a compliant ADU application
• 60-day approval deadline — cities must act within 60 days of a complete application

These laws mean a well-prepared plan set gets approved faster and with fewer obstacles. That's why the quality of your drawings matters.

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The Smartest Way to Start Your ADU Project

The biggest mistake homeowners make is hiring a contractor before they have plans. You can't get accurate bids without drawings, and you can't get drawings approved without a permit.

The right sequence:

1. Get permit-ready plans from a qualified designer
2. Submit for plan check
3. Use the plan check period to get contractor bids
4. Start construction the day your permit is issued

Use our free cost calculator to get an instant estimate for your specific ADU. Or call David directly at 916-694-9949 — no hold, no sales team, just a straight answer about your project.