Building Code Glossary
Flush Valve: Building Code Definition
How the IRC 2009 define flush valve, 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
Flush valve is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “A device located at the bottom ofa flush tank that is operated to flush water closets.” No other I-Code in this corpus defines it, so the IRC 2009 definition is the one to work from. The term is used in 3 chapters of this corpus, most often in Plumbing Fixtures (IRC 2009), Definitions (IPC 2009), Definitions (IRC 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?
Flush Valve — IRC 2009, Definitions:
A device located at the bottom ofa flush tank that is operated to flush water closets.
What must be verified before using this guidance?
Flush Valve is defined once in this corpus, in the Definitions chapter of the International Residential Code (IRC) 2009:
A device located at the bottom ofa flush tank that is operated to flush water closets.
Where flush valve is used in the code
The term appears in 3 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Plumbing Fixtures | IRC 2009 | 3 |
| Definitions | IPC 2009 | 1 |
| Definitions | IRC 2009 | 1 |
The term in use
How the code actually writes about flush valve, quoted from the 2009 text hosted here:
Flush valve seats in tanks for flushing water closets shall be at least 1 inch (25 mm) above the flood-level rim of the bowl connected thereto, except an approvedwater closet and flush tank combination designed so that when the tank is flushed and the fixture is clogged or partially clogged, the flush valve will close tightly so that water will …
The terms flush valve is built out of
The definition above leans on 2 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what flush valve covers:
- Flush Tank — IPC 2009: A tank designed with a fill valve and flush valve to flush the contents of the bowl or usable portion of the fixture.
- Device — IRC 2009: Aunit of an electrical system that carries or controls electrical energy as it principal function.
Flush Valve: 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 | |
| Re-check the requirement that uses it | Plumbing Fixtures (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| Confirm the dependent definition | Flush Tank | |
| Confirm the dependent definition | Device | |
| 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?
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 flush valve?
The International Residential Code (IRC) 2009 defines it in Definitions as: “A device located at the bottom ofa flush tank that is operated to flush water closets.” 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 flush valve?
In this corpus the term is used across 3 chapters, led by Plumbing Fixtures in the IRC 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 a flush valve on a commercial toilet?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “A device located at the bottom ofa flush tank that is operated to flush water closets.” It is defined in IRC 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 is the IRC plumbing code?
Plumbing is a separate defined term. The IRC 2009 defines it as: “For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33.” That is not the same as flush valve, which the IRC 2009 defines as “A device located at the bottom ofa flush tank that is operated to flush water closets.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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