Building codes are standards created by building industry trade groups and adopted by local jurisdictions. The codes lay out prescribed methods and minimum standards for construction. Building codes are enforced by local government inspectors who conduct site inspections during construction. The most commonly adopted set of codes for residential construction is the International Residential Code (IRC) published by the International Code Council. Building codes are typically updated every three years, although local adoption may lag as rules are added or IRC codes are modified. In some geographic areas, such as property outside city limits, code compliance may be handled by private inspectors, or it may not be enforced at all. It is important to know that building code compliance IS NOT normally part of the purchase and sale of real estate. Appraisers and home inspectors may note code issues or concerns on reports, but they do not certify if buildings comply with codes.