HVAC changeout, water heater, and other trade permits (mechanical, plumbing, electrical, gas)

The FAQ requires a permit to "erect, install, enlarge, alter, repair, remove, convert, or replace any electrical, gas, mechanical, or plumbing system" — which by its terms covers an HVAC changeout and a water heater replacement. Trade permit process (Town Building Permits page): "If you would like a trade permit (mechanical, plumbing, electrical or gas) for a job site that has a master permit, or for a standalone permit you can apply via our online portal. Trade permits are issued by our Front Office staff and are typically issued same day if they are attached to a master permit. If your trade permit is not related to a master building permit, then please contact us in regard to what plans (if any) may be needed for permit issuance or currently review time." Trade permit questions: (843) 884-5184. Flood-zone note: under § 152.20(E) electrical, heating, ventilation, plumbing, air conditioning and permanent/fixed generator equipment and ductwork shall not be located below the design flood elevation in new construction and substantial improvement construction; under § 152.20(K), new or replacement electrical/heating/ventilation/plumbing/AC equipment installed in non-compliant buildings, where substantial improvement or damage is not a factor, "shall be elevated to at least the existing lowest floor level."