Does Indiana use the IPC or the UPC for plumbing?

Indiana is the rare Midwest state that adopts the Uniform Plumbing Code (UPC) rather than the International Plumbing Code (IPC). The state-level rule lives at 675 IAC 16 and applies to every Marion County remodel that touches drain-waste-vent geometry, fixture counts, water heater venting, or potable-water rough-ins. Ohio, Michigan, Illinois, and Kentucky all run the IPC, so plumbers and designers crossing the border need to recalibrate -- the two codes diverge on trap-arm distances, vent stack sizing, fixture-unit weighting, and where you can use AAVs.

What this means on a kitchen or bath remodel in Indianapolis: your plumber must hold an active Indiana Plumbing Contractor license issued by the Indiana Professional Licensing Agency (PLA), and the permit application filed with the Department of Business and Neighborhood Services (DBNS) names that licensee as plumber of record. Homeowners cannot legally pull their own plumbing permits except on owner-occupied single-family dwellings, and even then the work has to pass the same UPC rough-in and final inspections.

A few practical UPC differences that bite remodels: the UPC counts fixtures using Drainage Fixture Units (DFUs) with a different weighting table than the IPC, so a bath group sized fine in Cincinnati may need an upsized stack in Indy. Vent terminations have stricter clearance rules from openable windows and roof eaves. Studor-style air admittance valves are allowed in narrower circumstances than the IPC permits. Tubular trap arms have a maximum developed length you should verify before locking cabinet layout.

If you are working with an out-of-state designer or plumber, ask up front whether they have built recently in Indiana -- a UPC-fluent local plumber will save permit cycles. Inspections schedule through DBNS Permits and Licenses; rough-in passes before drywall, final passes before occupancy.

Want Baily to flag UPC-vs-IPC issues in a contractor bid you already have, or surface plumbers who hold an active Indiana PLA license? Drop the bid or your zip code into chat and we will walk through it.