Do I need a permit to finish a basement?

Yes — virtually all US municipalities require permits for basement finishing because the work involves electrical, framing, often plumbing, and egress changes. Permits typically cost $400–$1,500 depending on jurisdiction and project scope. The single critical permit-driven cost is egress windows: any room used as a bedroom needs an egress window (typically $2,500–$6,000 installed including the well). Skipping the permit voids your homeowners insurance for any basement-related claim, blocks resale (an unpermitted bedroom can't be listed as a bedroom), and triggers fines + forced rip-out 10–15% of the time when discovered.