Research: Permit Rules Compared Across U.S. Cities

Each page here asks one question of every city we have researched from primary sources and answers it with the city’s own code section, exempt-work list or fee schedule. The rows link to the city pages that quote the documents, the tables download as CSV, and everything is published under CC BY 4.0 with attribution by link.

Research · October 2026 Where Can You Build an ADU? 30 Cities Compared 22 of the 30 largest U.S. cities we cover allow an accessory dwelling unit by right, 3 only in some districts, 2 with major limits, Dallas by special exception only, and Baltimore and Pittsburgh not yet. Nine cities require the owner to live on site; size caps run from 720 to 1,600 sq ft. Sourced city by city. Research · October 2026 Do You Need a Permit to Build a Fence? 30 Cities Compared In 18 of the 30 largest U.S. cities we cover, a 6-foot wood fence in the back yard needs no permit and no filing. Five cities require a building permit for every new fence, five want a zoning filing for every fence, and the exemption height runs from 3 ft in Phoenix to 10 ft in Los Angeles. Sourced city by city. Research · October 2026 What Size Shed Can You Build Without a Permit? 30 Cities Compared The permit-free shed size runs from 100 to 300 sq ft across the 30 largest U.S. cities we cover, 4 cities exempt no shed at all, Los Angeles uses a dollar value instead, and 3 cities publish two different numbers. Sourced city by city. Research · October 2026 Do You Need a Permit to Replace a Toilet? 30 Cities Compared 13 of 30 big U.S. cities require a plumbing permit for a same-spot toilet replacement, 13 exempt it, and 4 contradict their own guidance. Sourced city by city.

How these comparisons are built

BuildPermitGuide rewrites its city pages from the documents the city publishes: the adopted building and plumbing codes, the department’s exempt-work list, the current fee schedule and the permit portal’s own instructions. Each page quotes the language it relies on and records where two city documents disagree. A research page takes one question, reads the answer off each rewritten page, and reports it without resolving a conflict the city itself has not resolved. See the methodology and the change log that tracks the cited documents.