Whether a permit is needed for a particular task depends on state, county and city regulations, although permitting is typically required for new structures, water heaters and plumbing and electrical work. Although permits can be expensive, performing work without a permit can lead to heavy fines.
Permitting is required to ensure safety and make sure only trained professionals perform certain tasks. Large renovations often require permits, as do renovations that affect a home's plumbing and electrical infrastructure. Even seemingly minor tasks may require permitting. Moving a sink, for example, requires plumbing work and may demand a permit.
Determining whether a particular job requires a permit generally involves finding local regulation, which may be available online. Licensed contractors typically have extensive experience with the permitting process and generally handle the work involved in obtaining approval. Contractors also know how to supply needed information; many permits require plans drawn by an expert.
Permits can cost hundreds of dollars, and large jobs may demand thousands of dollars in permitting. However, inspectors and local officials who uncover work performed without a permit can levy significant fines. If the work is done safely, homeowners may be able to apply for a permit retroactively. However, unpermitted work, especially if its deemed unsafe, can cause a city official to deem a home unfit for occupancy until the home is restored to its previous state.