Home Improvement Permits: When You Need One (and When You Don't)

Almost always requires a permit

• Structural changes (removing walls, altering rooflines)
• New electrical circuits or panel upgrades
• Plumbing rough-in changes (moving drains, adding fixtures)
• New windows/doors that change the opening size
• Decks over 30" above grade, most detached structures over 120 sq ft
• Water heater replacement (yes, really, in most jurisdictions)

Usually permit-exempt

• Paint, wallpaper, tile, flooring, carpet
• Cabinet or countertop swaps that reuse existing plumbing
• Like-for-like fixture swaps (faucet, toilet, disposal)
• Fences under 6–7 ft depending on the city

What happens if you skip a permit

Best case: nothing until you sell, at which point the buyer's inspector flags the work and you either tear it out, retrofit under an 'after-the-fact' permit (2–4x normal fee), or discount the sale price. Worst case: an injury or fire during the un-permitted work voids your homeowner's insurance claim.