Plumbing permits — fixture moves, water heaters, and reroutes

Plumbing work is regulated for two main reasons: protecting the potable water supply from contamination, and protecting the building from leaks and water damage. Most jurisdictions require a permit for any work that touches the water supply, the drain-waste-vent system, or gas piping. Plumbing reviewers also coordinate with the local water utility on backflow protection and with the gas utility on gas-line integrity, which is why even small plumbing changes can trigger more review than homeowners expect. When a permit is required. New plumbing fixtures, fixture relocations, repipes, water heater replacements (in many jurisdictions, including like-for-like), tankless water heater installation, water service line replacement, sewer service line replacement, gas piping changes, and backflow preventer installation. Like-for-like fixture replacements that do not change the rough-in are usually exempt, but tankless conversions, gas-line extensions, and any work that adds new fixtures are almost never exempt. Application package. The plumbing permit application asks for a description of the work, the fixtures involved, the location, and the contractor's license number. For a repipe or major reroute, a sketch showing the new plumbing layout is usually required. For tankless or high-efficiency water heater installations, the manufacturer installation instructions and a venting plan are commonly requested. Typical fees. $80 to $220 for residential plumbing work, calculated by fixture count or as a flat fee for simple permits. Sewer- and water-service replacements often carry higher fees because they include a right-of-way component and may require a separate utility coordination fee. Licensing. Plumbing work generally must be performed by a licensed plumber, with the same owner-builder exemptions that apply to other trades. Some jurisdictions further restrict gas piping to plumbers or HVAC contractors with a gas endorsement; confirm before you plan to do gas work yourself. Inspections. Rough inspection (drain-waste-vent piping in place, before walls are closed, often with a water or air test) and final inspection (after fixtures are installed and the system is operational). Water heater changeouts often require only a final inspection. Gas piping requires a separate pressure test before being put back in service. Sewer replacements typically require an open-trench inspection before backfill. What inspectors check. Pipe materials and sizes, slope of drain piping, venting (air admittance valve use is restricted in many jurisdictions), backflow protection at hose bibs and irrigation, water heater venting and TPR discharge, gas piping support and pressure test, expansion-tank installation on closed water systems, and that all fixtures are accessible and functional. Pressure-reducing valves and thermostatic mixing valves on hot water are checked where required by local amendment.