Building Code Glossary
Indirect Waste Pipe: Building Code Definition
How the IRC 2009, IPC 2009 define indirect waste pipe, 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
Indirect waste pipe is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “A waste pipe that discharges into the drainage system through an air gap into a trap, fixture or receptor.” 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 7 chapters of this corpus, most often in Indirect/special Waste (IPC 2009), Definitions (IPC 2009), Sanitary Drainage (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?
Indirect Waste Pipe — IRC 2009, Definitions:
A waste pipe that discharges into the drainage system through an air gap into a trap, fixture or receptor.
What must be verified before using this guidance?
Two of the I-Codes in this corpus define Indirect Waste Pipe, and the wording is not identical — read the version that governs your question.
| Code | Where it is defined | Definition |
|---|---|---|
| IRC 2009 | Definitions | A waste pipe that discharges into the drainage system through an air gap into a trap, fixture or receptor. |
| IPC 2009 | Definitions | A waste pipe that does not connect directly with the drainage system, but that discharges into the drainage system through an air break or airgap into a trap, fixture, receptor or interceptor. |
Where indirect waste pipe is used in the code
The term appears in 7 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Indirect/special Waste | IPC 2009 | 21 |
| Definitions | IPC 2009 | 2 |
| Sanitary Drainage | IPC 2009 | 2 |
| Water Heaters | IPC 2009 | 2 |
| Definitions | IRC 2009 | 2 |
| Water Heaters | IRC 2009 | 2 |
| Plumbing Fixtures | IRC 2009 | 1 |
The term in use
How the code actually writes about indirect waste pipe, quoted from the 2009 text hosted here:
Food-handling equipment and clear-water waste shall discharge through an indirect waste pipe as specified in Sections 802.1.1 through 802.1.8.
All sterilizers, steamers and condensers shall discharge to the drainage through an indirect waste pipe by means of an airgap.
The pan shall be drained by an indirect waste pipe having a minimum diameter of ¾ inch (19 mm).
The terms indirect waste pipe 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 indirect waste pipe covers:
- Drainage System — IPC 2009: Piping within a public or private premise that conveys sewage, rainwater or other liquid wastes to a point of disposal.
- Interceptor — IPC 2009: A device designed and installed to separate and retain for removal, by automatic or manual means, deleterious, hazardous or undesirable matter from normal wastes, while permitting normal sewage or wastes to discharge into the drainage system by gravity.
- Receptor — IRC 2009: A fixture or device that receives the discharge from indirect waste pipes.
- System — IFC 2009: An assembly of equipment consisting of a tank, container or containers, appurtenances, pumps, compressors and connecting piping.
- Waste — IRC 2009: Liquid-borne waste that is free of fecal matter.
Indirect Waste Pipe: 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 | Indirect/special Waste (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | Sanitary Drainage (IPC 2009) | |
| Re-check the requirement that uses it | Water Heaters (IPC 2009) | |
| Confirm the dependent definition | Drainage System | |
| Confirm the dependent definition | Interceptor | |
| Confirm the dependent definition | Receptor | |
| 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
- Drainage System: Building Code Definition
- Interceptor: Building Code Definition
- Receptor: Building Code Definition
- System: 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 indirect waste pipe?
The International Residential Code (IRC) 2009 defines it in Definitions as: “A waste pipe that discharges into the drainage system through an air gap into a trap, fixture or receptor.” 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 indirect waste pipe?
In this corpus the term is used across 7 chapters, led by Indirect/special Waste 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 an indirect waste pipe?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “A waste pipe that discharges into the drainage system through an air gap into a trap, fixture or receptor.” 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.
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