Building Permit

A building permit is official authorization from the local authority having jurisdiction — usually a city or county building department — to perform construction work. Its purpose is to ensure the work meets adopted building, electrical, plumbing, mechanical, and zoning codes, verified through plan review and inspections. In short, the permit is how a jurisdiction confirms that what you build is safe and legal.

As a general rule, a permit is required for new structures, additions, structural alterations, and changes to electrical, plumbing, or mechanical systems — including any new ADU. Smaller cosmetic work like painting or flooring often does not require one, though thresholds vary by jurisdiction. The process generally runs from preparing plans, to submitting an application and paying fees, to plan review (which may return correction comments), to issuance, and finally to inspections during construction.

Fees are commonly tied to the project's permit valuation — the estimated cost of construction — so larger projects pay more, sometimes alongside separate plan-review and impact fees. During construction, inspections verify the work matches the approved plans at key stages such as foundation, framing, and rough systems. After the final inspection passes, the jurisdiction typically issues a certificate of occupancy confirming the space is safe and legal to occupy.

Building without a required permit can trigger stop-work orders, fines, mandatory correction, and problems at resale, so it is rarely worth the shortcut. Permit records are also public, which makes them a valuable signal of where construction is happening. Requirements and fee schedules differ by jurisdiction, so confirm specifics with your local building department before starting work.