Do you need a permit for a shed?
Sometimes. Ask the authority having jurisdiction before ordering or building it. Local examples prove why a national cutoff is misleading. Seattle waives a shed permit only when all listed conditions are met, including a roof footprint of 120 square feet or less, one story, specified simple support, no attachment, not in or near an environmentally critical area, and generally unoccupied use. (Seattle SDCI shed rules)
Portland uses a different trigger: its residential page says a permit is required to build, demolish, or move a structure over 200 square feet or over 15 feet high, with a separate 400-square-foot provision for certain parcels over two acres when distance conditions are met. (Portland residential permit rules)
The practical answer comes from your city or county, the property address, the exact shed dimensions and height, its foundation and use, its location on the lot, and whether it will have power, plumbing, heat, or other regulated work.
A building-permit exemption is not a project exemption
Seattle expressly says that a shed must meet building, land-use, stormwater, grading, and environmentally critical-area code requirements whether or not it needs a permit. (Seattle SDCI shed rules) The city’s page also lists lot coverage, height, and yard-location limits.
That distinction matters everywhere: a building department may exempt a small structure from plan review while zoning or land-use rules still control setbacks, height, lot coverage, easements, drainage, floodplain placement, historic review, or use. Homeowner-association covenants are another separate layer.
Start by separating the questions in our building permit versus zoning permit guide. A “no building permit required” answer is complete only after the zoning and site questions are resolved too.
Which permits or approvals might apply?
- Building or construction permit: structure, foundation, dimensions, anchorage, framing, and life-safety review where required.
- Zoning or land-use approval: setbacks, height, lot coverage, placement, use, critical areas, overlays, and design rules.
- Electrical permit: a feeder, branch circuit, receptacles, lighting, heat, equipment, or service change can create a separate permit and inspection path. Seattle notes that a shed project may require an electrical service change or new service application. (Seattle SDCI shed rules)
- Plumbing permit: water, drainage, fixtures, or sewer connections can trigger separate review.
- Site, grading, stormwater, floodplain, or environmental review: location and ground work can matter even when the shed itself is small.
- Historic or neighborhood approval: designated properties or local overlays may add review.
If the building will be occupied, slept in, rented, used for a business, or fitted as a dwelling, stop calling it a storage shed. A proposed living unit belongs in the ADU permit guide and requires a different code analysis.
What inspections should you expect?
Ask the permit office for the inspection sequence tied to the issued permit rather than assuming one generic shed schedule. Depending on the approved scope, inspections can occur before concrete or anchors are concealed, after framing and structural connections, during electrical or plumbing rough-in, and at final completion. Site or zoning staff may also verify location, setbacks, height, drainage, or critical-area conditions.
Do not cover work until the responsible inspector releases it. Save the approved plans, permit card, inspection results, photos of concealed work, product approvals, and final sign-off with the property records.
What does a real exemption look like?
A real exemption is a list of conditions, not just a floor-area number. Seattle’s exemption requires all of its criteria to be met; if one fails, the no-permit conclusion fails. Portland’s page adds a height trigger and special parcel-size and separation conditions to its accessory-structure rules. (Portland residential permit rules)
Before using an exemption, record:
- roof footprint and floor area under the local measuring rule;
- maximum height and number of stories;
- detached or attached status;
- foundation or support type;
- use and whether anyone will occupy it;
- distance from property lines, buildings, easements, utilities, slopes, wetlands, and flood-prone areas;
- electrical, plumbing, mechanical, or utility work; and
- the code page, written determination, or permit-office response used.
Do not average Seattle’s 120-square-foot rule and Portland’s 200-square-foot rule into a national “typical threshold.” Their differences are the lesson.