Building Code Glossary
Fill Valve: Building Code Definition
How the IPC 2009 define fill 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
Fill valve is a defined term in the International Plumbing Code (IPC) 2009, in Definitions. The code's own words are: “A water supply valve, opened or closed by means of a float or similar device, utilized to supply water to a tank. An antisiphon fill valve contains an antisiphon device in the form of an approved air gap or vacuum breaker that is an integral part of the fill valve unit and that is positioned …” 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 4 chapters of this corpus, most often in Fixtures, Faucets and Fixture Fittings (IPC 2009), Water Supply and Distribution (IRC 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?
Fill Valve — IPC 2009, Definitions:
A water supply valve, opened or closed by means of a float or similar device, utilized to supply water to a tank. An antisiphon fill valve contains an antisiphon device in the form of an approved air gap or vacuum breaker that is an integral part of the fill valve unit and that is positioned on the discharge side of the water supply control valve.
What must be verified before using this guidance?
Fill Valve is defined once in this corpus, in the Definitions chapter of the International Plumbing Code (IPC) 2009:
A water supply valve, opened or closed by means of a float or similar device, utilized to supply water to a tank. An antisiphon fill valve contains an antisiphon device in the form of an approved air gap or vacuum breaker that is an integral part of the fill valve unit and that is positioned on the discharge side of the water supply control valve.
Where fill valve 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 |
|---|---|---|
| Fixtures, Faucets and Fixture Fittings | IPC 2009 | 6 |
| Water Supply and Distribution | IRC 2009 | 6 |
| Definitions | IPC 2009 | 4 |
| Water Supply and Distribution | IPC 2009 | 4 |
The term in use
How the code actually writes about fill valve, quoted from the 2009 text hosted here:
All flush tanks shall be equipped with an antisiphon fill valve conforming to ASSE 1002 or CSA B125.3.
Flush tanks shall be equipped with an antisiphon fill valve conforming to ASSE 1002 or CSA B125.3.
Potable water inlets to gravity tanks shall be controlled by a fill valve or other automatic supply valve installed so as to prevent the tank from overflowing.
The terms fill valve 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 fill valve covers:
- Vacuum Breaker — IPC 2009: A type of backflow preventer installed on openings subject to normal atmospheric pressure that prevents backflow by admitting atmospheric pressure through ports to the discharge side of the device.
- Antisiphon — IRC 2009: A term applied to valves or mechanical devices that eliminate siphonage.
- Approved — IBC 2009: Acceptable to the code official or authority having jurisdiction.
- Control — IRC 2009: A manual or automatic device designed to regulate the gas, air, water or electrical supply to, or operation of, a mechanical system.
- Device — IRC 2009: Aunit of an electrical system that carries or controls electrical energy as it principal function.
Fill 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 IPC | Definitions | |
| Re-check the requirement that uses it | Fixtures, Faucets and Fixture Fittings (IPC 2009) | |
| Re-check the requirement that uses it | Water Supply and Distribution (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | Water Supply and Distribution (IPC 2009) | |
| Confirm the dependent definition | Vacuum Breaker | |
| Confirm the dependent definition | Antisiphon | |
| 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
- Vacuum Breaker: Building Code Definition
- Antisiphon: Building Code Definition
- Approved: Building Code Definition
- Control: 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 fill valve?
The International Plumbing Code (IPC) 2009 defines it in Definitions as: “A water supply valve, opened or closed by means of a float or similar device, utilized to supply water to a tank. An antisiphon fill valve contains an antisiphon device in the form of an approved air gap or vacuum breaker that is an integral part of the fill valve unit and that is positioned on the discharge side of the water supply control valve.” 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 fill valve?
In this corpus the term is used across 4 chapters, led by Fixtures, Faucets and Fixture Fittings 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 a fill valve used for?
In the 2009 I-Codes hosted here it is a defined term rather than a description. The IPC 2009 states, in Definitions: “A water supply valve, opened or closed by means of a float or similar device, utilized to supply water to a tank. An antisiphon fill valve contains an antisiphon device in the form of an approved air gap or vacuum breaker that is an integral part of the fill valve unit and that is positioned …” 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.
What does IPC mean in plumbing?
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 fill valve, which the IPC 2009 defines as “A water supply valve, opened or closed by means of a float or similar device, utilized to supply water to a tank. An antisiphon fill valve contains an antisiphon device in the form of an approved air gap or vacuum …” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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