Knowledge Base

When is a building permit required?

Building permits are required to erect, enlarge, alter, move, demolish, or repair any structure in the City of Thornton. This includes everything from fences and decks to residential and commercial new construction or remodels.   

  • Electrical permits are required for the installation of new electrical service equipment, existing service relocations, service increases, and fixed appliances and equipment connections.
  • Mechanical permits are required for the replacement or alteration of mechanical systems. This includes furnaces, air conditioning units, evaporative coolers, gas lines, propane tanks, and associated piping for flammable liquids.
  • Plumbing permits are required for all plumbing work, including water service, sewer replacement, drains, sprinkler systems, water heaters, water softener Systems and related fixtures and appliances.
  • Permits are also required for mobile home set-ups, signage and retaining walls over four feet above grade.  

Examples of the types of projects that require and do not require permits are available on the Permit Requirements web page.  

Additional information is available on the Building Inspections web page.

Updated 6/1/2021 3:59 PM
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