Thornton, CO Building Safety: Plumbing Permits (2026)

Section 10-153 adopts the International Plumbing Code, 2024 edition, published by the International Code Council, in full including its outline of contents and index, but excludes all appendix chapters except Appendix E; local amendments to specific IPC sections are layered on in Section 10-154. Because plumbing installations fall within the definition of work regulated by the Building Code, plumbing work follows the same building permit machinery: an application under Section 10-61, plan review and permit fees set by resolution under Section 10-62, and mandatory inspections under Section 10-64, which specifically call out a rough-in plumbing inspection covering the water or air test on potable water, waste and vent piping before it is covered, followed by a final inspection once fixtures are set and the system is operating.

Only a licensed contractor may perform this work; Thornton's contractor licensing table designates a Class D Plumbing classification that requires a valid State of Colorado Plumbing Contractor license and Master Plumber license before the city will issue that license, reflecting the cross-referenced state law that bars the city from separately testing or regulating plumbers itself. A homeowner performing plumbing work on their own principal residence is not treated as a contractor and does not need this license, but the plumbing work itself is still subject to permit, plan review where required, and inspection under the adopted IPC.