Building Code Glossary
Flushometer Tank: Building Code Definition
How the IRC 2009, IPC 2009 define flushometer tank, 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
Flushometer tank is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “A device integrated within an air accumulator vessel that is designed to discharge a predetermined quantity of water to fixtures for flushing purposes.” The IPC 2009 carries the same definition word for word, so the term means the same thing in each. The term is used in 4 chapters of this corpus, most often in Definitions (IPC 2009), Fixtures, Faucets and Fixture Fittings (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?
Flushometer Tank — IRC 2009, Definitions:
A device integrated within an air accumulator vessel that is designed to discharge a predetermined quantity of water to fixtures for flushing purposes.
What must be verified before using this guidance?
Two of the I-Codes in this corpus define Flushometer Tank, in identical words.
| Code | Where it is defined | Definition |
|---|---|---|
| IRC 2009 | Definitions | A device integrated within an air accumulator vessel that is designed to discharge a predetermined quantity of water to fixtures for flushing purposes. |
| IPC 2009 | Definitions | A device integrated within an air accumulator vessel that is designed to discharge a predetermined quantity of water to fixtures for flushing purposes. |
Where flushometer tank is used in the code
The term appears in 4 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.
| Chapter | Code | Mentions |
|---|---|---|
| Definitions | IPC 2009 | 1 |
| Fixtures, Faucets and Fixture Fittings | IPC 2009 | 1 |
| Definitions | IRC 2009 | 1 |
| Plumbing Fixtures | IRC 2009 | 1 |
The term in use
How the code actually writes about flushometer tank, quoted from the 2009 text hosted here:
Each water closet, urinal, clinical sink and any plumbing fixture that depends on trap siphonage to discharge the fixture contents to the drainage system shall be provided with a flushometer valve, flushometer tank or a flush tank designed and installed to supply water in quantity and rate of flow to flush the contents of the fixture, cleanse the fixture and …
Water closets shall be provided with a flush tank, flushometer tank or flushometer valve designed and installed to supply water in sufficient quantity and flow to flush the contents of the fixture, to cleanse the fixture and refill the fixture trap in accordance with ASME AI12.19.2 and ASME AI12.19.6.
The terms flushometer tank 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 flushometer tank covers:
- Vessel — IFC 2009: A motorized watercraft, other than a seaplane on the water, used or capable of being used as a means of transportation.
- Device — IRC 2009: Aunit of an electrical system that carries or controls electrical energy as it principal function.
Flushometer Tank: 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 | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | Fixtures, Faucets and Fixture Fittings (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| Re-check the requirement that uses it | Plumbing Fixtures (IRC 2009) | |
| Confirm the dependent definition | Vessel | |
| 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 flushometer tank?
The International Residential Code (IRC) 2009 defines it in Definitions as: “A device integrated within an air accumulator vessel that is designed to discharge a predetermined quantity of water to fixtures for flushing purposes.” 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 flushometer tank?
In this corpus the term is used across 4 chapters, led by Definitions 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 are the key differences between a flushometer valve and a flush tank?
Flushometer Valve is a separate defined term. The IRC 2009 defines it as: “A flushometer valve is a device that discharges a predetermined quantity of water to fixtures for flushing purposes and is actuated by direct water pressure.” That is not the same as flushometer tank, which the IRC 2009 defines as “A device integrated within an air accumulator vessel that is designed to discharge a predetermined quantity of water to fixtures for flushing purposes.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
What is a water closet flush valve?
Flush Valve is a separate defined term. The IRC 2009 defines it as: “A device located at the bottom ofa flush tank that is operated to flush water closets.” That is not the same as flushometer tank, which the IRC 2009 defines as “A device integrated within an air accumulator vessel that is designed to discharge a predetermined quantity of water to fixtures for flushing purposes.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
What is the difference between a flush tank and a flushometer tank?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “A device integrated within an air accumulator vessel that is designed to discharge a predetermined quantity of water to fixtures for flushing purposes.” It is defined in IRC 2009, IPC 2009. It is not the same as Flush Tank, which the IPC 2009 defines separately as “A tank designed with a fill valve and flush valve to flush the contents of the bowl or usable portion of the fixture.” 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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