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Granny Flat Prices United States
Prices do not include sales tax. ADU regulations vary significantly by state and city. California, Oregon, and Washington have the most permissive ADU laws. Allow 4–9 months from permit to completion.
Granny Flat Prices by Type — United States
Prices do not include sales tax. ADU regulations vary significantly by state and city. California, Oregon, and Washington have the most permissive ADU laws. Allow 4–9 months from permit to completion.
| Service | Unit | From | Average | Up to |
|---|---|---|---|---|
| 🏠1-Bedroom ADU (430 sq ft) Complete 1-bedroom accessory dwelling unit with kitchen, bathroom, and living area | /job | $64,000 | $88,000 | $112,000 |
| 🏡2-Bedroom ADU (645 sq ft) Full 2-bedroom ADU with kitchen, bathroom, laundry, and living area | /job | $96,000 | $128,000 | $160,000 |
| 🛖Studio ADU (270 sq ft) Compact open-plan studio ADU with kitchenette and bathroom | /job | $44,000 | $58,000 | $72,000 |
| 📦Prefab ADU (1-bed) Factory-built prefabricated 1-bedroom ADU delivered and assembled on site | /job | $40,000 | $58,000 | $76,000 |
| ✏️Custom-Designed ADU Architect-designed custom ADU with premium finishes and unique layout | /job | $120,000 | $172,000 | $224,000 |
| 🚗ADU with Garage ADU with integrated or attached single-car garage | /job | $112,000 | $156,000 | $200,000 |
| ♿ADA-Accessible ADU Fully ADA-compliant ADU with accessible bathroom, wider doorways, and ramp | /job | $80,000 | $112,000 | $144,000 |
| 📋Permits & Planning Building permits, zoning review, and plan check fees | /job | $4,000 | $8,000 | $12,000 |
| 🏗️Site Preparation & Foundation Site clearing, grading, utility trenching, and concrete slab foundation | /job | $12,000 | $20,000 | $28,000 |
| 🔨ADU Renovation/Conversion Convert or renovate an existing structure into a legal ADU | /job | $32,000 | $56,000 | $80,000 |
| 🚚Modular/Transportable ADU Pre-built modular ADU delivered and craned into position | /job | $48,000 | $72,000 | $96,000 |
| 🔌ADU with Separate Utilities ADU with independent water, electric, and sewer connections | /job | $104,000 | $140,000 | $176,000 |
Granny Flat Prices by City
Click a city for detailed local pricing and tips
Los Angeles
California · 3.9M
From $5,000
San Francisco
California · 870K
From $5,500
San Diego
California · 1.4M
Pricing available
San Jose
California · 1.0M
Pricing available
New York City
New York · 8.3M
Pricing available
Buffalo
New York · 280K
Pricing available
Houston
Texas · 2.3M
From $3,000
Dallas
Texas · 1.3M
Pricing available
Austin
Texas · 1.0M
From $3,500
San Antonio
Texas · 1.5M
Pricing available
Miami
Florida · 450K
From $4,000
Orlando
Florida · 310K
Pricing available
Tampa
Florida · 400K
Pricing available
Jacksonville
Florida · 950K
Pricing available
Chicago
Illinois · 2.7M
From $4,000
Philadelphia
Pennsylvania · 1.6M
Pricing available
Pittsburgh
Pennsylvania · 300K
Pricing available
Columbus
Ohio · 905K
Pricing available
Cleveland
Ohio · 370K
Pricing available
Atlanta
Georgia · 500K
From $3,500
Boston
Massachusetts · 680K
Pricing available
Seattle
Washington · 740K
From $4,500
Phoenix
Arizona · 1.6M
Pricing available
Denver
Colorado · 715K
From $3,800
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Granny flat costs in United States range from $4,000 for council approval and planning to $224,000 for a custom-designed build. Prices do not include sales tax. ADU regulations vary significantly by state and city. California, Oregon, and Washington have the most permissive ADU laws. Allow 4–9 months from permit to completion.
The most common options in United States are ADU / accessory dwelling unit / in-law suite. Services include 1-bedroom and 2-bedroom builds, studios, kit/prefab options, custom designs, accessible builds, council approval, site preparation, renovations, transportable units, and builds with separate services.
A standard granny flat in United States takes 12–20 weeks from slab to handover. Kit/prefab builds can be completed in 8–12 weeks. Custom designs may take 20–30 weeks. Council approval adds 2–24 weeks depending on the pathway.
Yes — all granny flats and secondary dwellings in United States require some form of building or planning approval. The specific requirements vary by state, territory, or local council. Your builder or certifier will advise on the correct approval pathway for your property.
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