Building Code Glossary
Leader: Building Code Definition
How the IPC 2009 define leader, 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
Leader is a defined term in the International Plumbing Code (IPC) 2009, in Definitions. The code's own words are: “An exterior drainage pipe for conveying storm water from roof or gutter drains to an approved means of disposal.” No other I-Code in this corpus defines it, so the IPC 2009 definition is the one to work from. The term is used in 8 chapters of this corpus, most often in Storm Drainage (IPC 2009), Roof Assemblies and Rooftop Structures (IBC 2009), Scope and Administration (IBC 2009). These pages transcribe the 2009 model text; verify the definition against the edition and amendments your authority having jurisdiction has adopted. Record the jurisdiction, the adopted edition, the application date and any local amendment that rewrites the definition before you use it on a live project, because a term redefined by amendment changes every requirement that depends on it.
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?
Leader — IPC 2009, Definitions:
An exterior drainage pipe for conveying storm water from roof or gutter drains to an approved means of disposal.
What must be verified before using this guidance?
Leader is defined once in this corpus, in the Definitions chapter of the International Plumbing Code (IPC) 2009:
An exterior drainage pipe for conveying storm water from roof or gutter drains to an approved means of disposal.
Where leader is used in the code
The term appears in 8 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Storm Drainage | IPC 2009 | 8 |
| Roof Assemblies and Rooftop Structures | IBC 2009 | 2 |
| Scope and Administration | IBC 2009 | 2 |
| Emergency Planning and Preparedness | IFC 2009 | 2 |
| Definitions | IPC 2009 | 2 |
| Roof Assemblies | IRC 2009 | 2 |
| Scope and Administration | IRC 2009 | 2 |
| Exterior Walls | IBC 2009 | 1 |
The term in use
How the code actually writes about leader, quoted from the 2009 text hosted here:
Strainers shall have an available inlet area, above roof level, of not less than one and one-half times the area of the conductor or leader to which the drain is connected.
The terms leader is built out of
The definition above leans on 1 other defined term. Each carries its own code definition, and a local amendment to any of them changes what leader covers:
- Approved — IBC 2009: Acceptable to the code official or authority having jurisdiction.
Leader: 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 IPC | Definitions | |
| Re-check the requirement that uses it | Storm Drainage (IPC 2009) | |
| Re-check the requirement that uses it | Roof Assemblies and Rooftop Structures (IBC 2009) | |
| Re-check the requirement that uses it | Scope and Administration (IBC 2009) | |
| Re-check the requirement that uses it | Emergency Planning and Preparedness (IFC 2009) | |
| Confirm the dependent definition | Approved | |
| 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
- Approved: Building Code Definition
- Building: Building Code Definition
- Construction Documents: Building Code Definition
- Registered Design Professional: 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 leader?
The International Plumbing Code (IPC) 2009 defines it in Definitions as: “An exterior drainage pipe for conveying storm water from roof or gutter drains to an approved means of disposal.” 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 leader?
In this corpus the term is used across 8 chapters, led by Storm Drainage 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 the definition of a building code?
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 leader, which the IPC 2009 defines as “An exterior drainage pipe for conveying storm water from roof or gutter drains to an approved means of disposal.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
What does leader mean?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IPC 2009 states, in Definitions: “An exterior drainage pipe for conveying storm water from roof or gutter drains to an approved means of disposal.” It is defined in 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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