Building Code Glossary
Plumbing: Building Code Definition
How the IRC 2009, IPC 2009 define plumbing, where the wording differs, and which chapters depend on the term.
On this page
Last updated September 7, 2026 · Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The [ICC code library](https://codes.iccsafe.org/codes) publishes the current model text and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-adoption-maps/) show which edition a jurisdiction has adopted; those sources control.
Direct answer
Plumbing is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33.” The IPC 2009 defines the same term with different wording, so the controlling text depends on which code governs the question in front of you — the comparison below sets the versions side by side. The term is used in 65 chapters of this corpus, most often in Scope and Administration (IPC 2009), General Regulations (IPC 2009), Definitions (IPC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted.
Content and cited inputs reviewed by Scott Barrington, Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.
What does this term mean?
Plumbing — IRC 2009, Definitions:
For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33.
What must be verified before using this guidance?
Two of the I-Codes in this corpus define Plumbing, and the wording is not identical — read the version that governs your question.
| Code | Where it is defined | Definition |
|---|---|---|
| IRC 2009 | Definitions | For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33. |
| IPC 2009 | Definitions | The practice, materials and fixtures utilized in the installation, maintenance, extension and alteration of all piping, fixtures, plumbing appliances and plumbing appurtenances, within or adjacent to any structure, in connection with sanitary drainage or storm drainage facilities; venting systems; and public or private water supply systems. |
Where plumbing is used in the code
The term appears in 65 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Scope and Administration | IPC 2009 | 91 |
| General Regulations | IPC 2009 | 38 |
| Definitions | IPC 2009 | 34 |
| Fixtures, Faucets and Fixture Fittings | IPC 2009 | 33 |
| Building Planning | IRC 2009 | 30 |
| Definitions | IRC 2009 | 26 |
| Plumbing Administration | IRC 2009 | 25 |
| General Plumbing Requirements | IRC 2009 | 21 |
| Plumbing Fixtures | IRC 2009 | 19 |
| Plumbing Systems | IBC 2009 | 18 |
| Scope and Administration | IBC 2009 | 17 |
| Water Supply and Distribution | IPC 2009 | 16 |
53 further chapters mention the term.
The term in use
How the code actually writes about plumbing, quoted from the 2009 text hosted here:
The provisions of this code shall apply to the erection, installation, alteration, repairs, relocation, replacement, addition to, use or maintenance of plumbing systems within this jurisdiction.
The provisions of this chapter shall govern the general regulations regarding the installation of plumbing not specific to other chapters.
This chapter shall govern the materials, design and installation of plumbing fixtures, faucets and fixture fittings in accordance with the type of occupancy, and shall provide for the minimum number of fixtures for various types of occupancies.
The terms plumbing is built out of
The definition above leans on 5 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what plumbing covers:
- Alteration — IBC 2009: Any construction or renovation to an existing structure other than repair or addition.
- Structure — IPC 2009: That which is built or constructed or a portion thereof.
- Private — IPC 2009: In the classification of plumbing fixtures, "private" applies to fixtures in residences and apartments, and to fixtures in nonpublic toilet rooms of hotels and motels and similar installations in buildings where the plumbing fixtures are intended for utilization by a …
- Venting — IRC 2009: Removal of combustion products to the outdoors.
- Piping — IRC 2009: Where used in this code, “piping” refers to either pipe or tubing, or both.
Plumbing: what to open, and in what order
Every row is a document this term depends on. The ICC code library and the ICC adoption maps cover the middle rows.
| Check | Where | Confirmed |
|---|---|---|
| Read the definition in the adopted IRC | Definitions | |
| Read the definition in the adopted IPC | Definitions | |
| Re-check the requirement that uses it | Scope and Administration (IPC 2009) | |
| Re-check the requirement that uses it | General Regulations (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | Fixtures, Faucets and Fixture Fittings (IPC 2009) | |
| Confirm the dependent definition | Alteration | |
| Confirm the dependent definition | Structure | |
| Confirm the dependent definition | Private | |
| Local amendment to any of the above | Jurisdiction's amendment list |
A research aid, not a code determination. The authority having jurisdiction decides which edition and which amendments apply.
Where can you explore related guidance?
- Explore all glossary guidance
- Alteration: Building Code Definition
- Structure: Building Code Definition
- Venting: Building Code Definition
- Private: Building Code Definition
Sources and method
Definitions quoted from the 2009 International Codes as transcribed in this site's building-codes collection, with the source chapter linked for each quotation. Usage counts are computed over the chapters hosted here, one copy per code. The ICC code library publishes the current model text and the ICC adoption maps show which edition a jurisdiction has adopted; those sources control.
Source links
Frequently asked questions
What is the code definition of plumbing?
The International Residential Code (IRC) 2009 defines it in Definitions as: “For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33.” The 2009 model text is reproduced here; the definition that binds your project is the one in the edition your jurisdiction has adopted, as amended locally.
Which parts of the code depend on plumbing?
In this corpus the term is used across 65 chapters, led by Scope and Administration in the IPC 2009. Those are the sections whose scope moves if the definition is amended locally, so read them together with Chapter 2 rather than on their own.
What is considered plumbing?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33.” It is defined in IRC 2009, IPC 2009. Because it is a defined term, whatever the adopted edition says it means is what every section using it means — so check Chapter 2 of that edition and any local amendment before relying on this wording.
What does IRC stand for in building codes?
Building is a separate defined term. The IBC 2009 defines it as: “Any structure used or intended for supporting or sheltering any use or occupancy.” That is not the same as plumbing, which the IRC 2009 defines as “For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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