Arizona to Delaware: master plumber license reciprocity

Delaware issues a person-held Master Plumber license through the Board of Plumbing, Heating, Ventilation, Air Conditioning and Refrigeration Examiners in the Division of Professional Regulation. 24 Del. C. § 1807 requires that license (or a statutory exemption) to provide plumbing services or to use the titles licensed plumber / master plumber. Employees, apprentices and journeymen work under a master's supervision without their own Board license. A new master needs a journeyman's certificate from a federally-standard apprenticeship plus two years under a master plumber (or similar-level licensee in another state), or seven years under such supervision plus the Delaware vocational-technical apprenticeship equivalency tests, then Board approval and the ProV-administered master plumber exam; the application fee is $173. Out-of-state masters apply by reciprocity under 24 Del. C. § 1810 without a Delaware exam: the Board shall grant the license if the origin state's standards are substantially similar, and otherwise requires at least seven years of practice after licensure. 24 DE Admin. Code 1800 § 2.3 requires every reciprocity applicant to submit the origin state's licensure laws and regulations so the Board can make that comparison. Licenses renew biennially; from the 2026 renewal, plumbing licensees complete 5 hours of continuing education (3 code, 1 safety, 1 cross-connections/backflow) by October 31 of even-numbered years.

Arizona does not issue a master plumber licence. A master plumber arriving from another state who only wants to work for an employer needs no Arizona licence (except a Phoenix journeyman card for permitted work in that city). To run a plumbing business the qualifying party must show four years of practical or management trade experience (at least two within the last ten years; up to two years creditable from accredited technical training), pass the open-book Arizona Statutes and Rules Exam (SRE, $61 through Gmetrix) and the plumbing trade exam ($66 through PSI) with at least 70% within two years of applying, complete a background check for every person named on the application, register the entity if an LLC, corporation or partnership, post a licence bond or recovery-fund assessment, and pay application and licence fees ($580 for C-37, $720 for R-37, $850 for CR-37 including the $370 Residential Recovery Fund assessment, before exam fees). The ROC pages verified for this entry describe no state-to-state reciprocity agreement; under A.A.C. R4-9-106(E) the Registrar may waive the trade exam when the qualifying party 'is currently or has previously been a qualifying party for a licensee in this state or another state in the same classification, or a comparable classification as determined by the Registrar, within the preceding five years' (Application to Waive a Trade Examination filed with the licence application, not pre-approved), and out-of-state experience counts toward the four-year requirement, but the SRE is never waived for out-of-state applicants. Individual master plumber licences from other states are not, by themselves, a waiver basis: the waiver turns on having qualified a contractor licence in a comparable classification.