Detached new build ADU Cost
A standalone backyard cottage built from the ground up. Most flexible and highest resale value, but the most expensive per square foot because everything — foundation, roof, utilities — is new.
Nationally a detached new build ADU runs $220–$360/sq ft turnkey. Below is a 600 sq ft example for every state, adjusted for local construction costs.
| State | 600 sq ft estimate | $/sq ft |
|---|---|---|
| Mississippi | $109,500–$179,500 | $183–$299 |
| Arkansas | $111,000–$181,500 | $185–$302 |
| Alabama | $112,000–$183,500 | $187–$306 |
| Oklahoma | $113,500–$186,000 | $189–$310 |
| South Carolina | $115,000–$188,000 | $191–$313 |
| North Carolina | $116,000–$190,000 | $194–$317 |
| Tennessee | $116,000–$190,000 | $194–$317 |
| Kansas | $116,000–$190,000 | $194–$317 |
| Louisiana | $116,000–$190,000 | $194–$317 |
| Georgia | $119,000–$194,500 | $198–$324 |
| Kentucky | $119,000–$194,500 | $198–$324 |
| Nebraska | $119,000–$194,500 | $198–$324 |
| New Mexico | $119,000–$194,500 | $198–$324 |
| South Dakota | $119,000–$194,500 | $198–$324 |
| West Virginia | $119,000–$194,500 | $198–$324 |
| Texas | $121,500–$198,500 | $202–$331 |
| Indiana | $121,500–$198,500 | $202–$331 |
| Iowa | $121,500–$198,500 | $202–$331 |
| Missouri | $121,500–$198,500 | $202–$331 |
| Florida | $125,500–$205,000 | $209–$342 |
| Ohio | $125,500–$205,000 | $209–$342 |
| Michigan | $125,500–$205,000 | $209–$342 |
| Idaho | $125,500–$205,000 | $209–$342 |
| North Dakota | $125,500–$205,000 | $209–$342 |
| Wyoming | $125,500–$205,000 | $209–$342 |
| Montana | $129,500–$211,500 | $216–$353 |
| Utah | $129,500–$211,500 | $216–$353 |
| Arizona | $129,500–$211,500 | $216–$353 |
| Virginia | $129,500–$211,500 | $216–$353 |
| Delaware | $132,000–$216,000 | $220–$360 |
| Wisconsin | $132,000–$216,000 | $220–$360 |
| Maine | $134,500–$220,500 | $224–$367 |
| Pennsylvania | $134,500–$220,500 | $224–$367 |
| Nevada | $134,500–$220,500 | $224–$367 |
| New Hampshire | $138,500–$227,000 | $231–$378 |
| Vermont | $138,500–$227,000 | $231–$378 |
| Colorado | $138,500–$227,000 | $231–$378 |
| Minnesota | $138,500–$227,000 | $231–$378 |
| Maryland | $138,500–$227,000 | $231–$378 |
| Oregon | $142,500–$233,500 | $238–$389 |
| Washington | $145,000–$237,500 | $242–$396 |
| Illinois | $145,000–$237,500 | $242–$396 |
| Rhode Island | $148,000–$242,000 | $246–$403 |
| Connecticut | $152,000–$248,500 | $253–$414 |
| New Jersey | $152,000–$248,500 | $253–$414 |
| Massachusetts | $158,500–$259,000 | $264–$432 |
| New York | $158,500–$259,000 | $264–$432 |
| Washington DC | $158,500–$259,000 | $264–$432 |
| California | $165,000–$270,000 | $275–$450 |
| Alaska | $171,500–$281,000 | $286–$468 |
| Hawaii | $178,000–$291,500 | $297–$486 |
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Other ADU types
Estimates are for planning only and are based on regional construction-cost indices and published statewide ADU statutes. Local ordinances, lot conditions and contractor pricing vary — always confirm with your city planning department and a licensed contractor.