Delaware — plumbing code & licensing

16 DE Admin. Code 4455 adopts the 2021 International Plumbing Code with Delaware amendments as the 2021 State of Delaware Plumbing Code; the final order in the Delaware Register of Regulations (26 DE Reg. 110, Aug. 1, 2022) makes it effective August 11, 2022. Per 16 Del.C. 7904 every political subdivision must enforce the IPC as adopted/modified by the Division of Public Health, with a local option to enforce the minimum standards of the most recently adopted IPC. LICENSING: Title 24, Chapter 18 assigns plumber licensure to the Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners (Division of Professional Regulation); the chapter licenses Master Plumbers only - apprentices/journeymen/mechanics may work under a licensed master without a state license of their own. OPEN GATE: the DPR board page itself was not opened firsthand in this lane (licensing read from the Title 24 Ch. 18 statutory text as republished and from 16 Del.C. 7906(b)'s cross-reference), so licensing URLs are blank and the row is partial. UPGRADE PASS 1 (2026-10-31): gate closed - the DPR board page (https://dpr.delaware.gov/boards/plumbers/) was opened firsthand: the Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners issues master plumber, master HVACR and master restricted HVACR licenses under 24 Del. C. ch. 18. licensing_authority, licensing_source_url and license_classes_url filled from that page. Status flipped to verified.