Home › Shed size without a permit
How Big a Shed Can You Build Without a Permit? Real Town Rules
Some links on this page are affiliate links. If you buy through them we may earn a commission at no extra cost to you. How we make money.
Four places, four rules
| Place | No building permit if (per the page) | Other conditions the page lists |
|---|---|---|
| Seattle, WA | Roof footprint 120 square feet or less; single story | Not attached to a house or other building. Not in or near an environmentally critical area. Used only for storage, growing plants or similar unoccupied purposes. May sit on a concrete slab, pier blocks or soil. Maximum height 12 feet. |
| San Luis Obispo County, CA (unincorporated) | Floor area 120 square feet or less, measured exterior wall to exterior wall; one story, detached | Check first if the shed has electrical or plumbing, or if the property is in the Coastal Zone. |
| Sherwood, OR | Under 200 square feet and under 12 feet average height | Accessory structures cannot exceed 15 feet. Detached structures of 100 to 200 square feet under 10 feet tall must be at least 3 feet from rear and side property lines. |
| Hopkins, MN | 200 square feet or less | A larger shed is treated as a new detached garage. All accessory structures need a 3 foot setback from rear and side lines, cannot be in an easement and must be anchored at all corners. |
Sources: the four city and county pages listed below. Sherwood's page is dated July 16, 2025; the others show no date.
What the sizes mean
By simple math: an 8x10 shed is 80 square feet, a 10x12 is 120, a 12x16 is 192 and a 12x20 is 240. A 10x12 fits all four limits above if the other conditions are met. A 12x16 fits only the 200 square foot places. Measure the way your town does.
Steps
- Find your building department's shed page or call. Ask for the size limit, the height limit, setbacks and whether a zoning review applies.
- Ask how size is measured: roof footprint, floor area or outside wall to outside wall.
- Ask about anything extra: electricity, plumbing, easements, flood or coastal zones, and your HOA.
- Get it in writing if you can.
For the code rule most towns start from, see Do I need a permit for a shed?
What will your shed cost?
Our free calculator compares building it yourself, buying a kit and hiring a builder for your exact size.
Open the shed cost calculatorCommon questions
How big can a shed be without a permit?
It depends on where you live. The four official pages we opened give 120 square feet (Seattle, San Luis Obispo County) or 200 square feet (Sherwood, Oregon; Hopkins, Minnesota). Our permit guide covers the 200 square foot figure in the International Residential Code.
Is the limit measured the same way everywhere?
No. Seattle uses roof footprint. San Luis Obispo County measures floor area from exterior wall to exterior wall. Sherwood says area and also an average height under 12 feet.
Does a shed under the limit need no approval at all?
Not always. Seattle says building, land use, stormwater, grading and critical-area codes apply whether or not you need a permit. Hopkins says setbacks and easement rules apply to all accessory structures. San Luis Obispo County says to check with Planning in the Coastal Zone.
Does electrical or plumbing change the answer?
Yes. San Luis Obispo County lists a shed that proposes electrical or plumbing as an exception to the permit exemption. Use a licensed electrician or plumber and check your local code.
What if my shed is bigger than the limit?
Hopkins, Minnesota says a shed over 200 square feet should be treated as a new detached garage. Seattle says most other sheds need a subject-to-field-inspection permit. Ask your building department.
Related guides
- Do I need a permit for a shed?
- 10x12 shed materials and cost
- 12x16 shed materials and cost
- How far should a shed be from the property line?
Free printable: Shed Build Checklist
From permit check to the last coat of paint, in one page. Download the one-page PDF now, or get it by email along with a short series of five helpful emails.