# Fixture Supply: Building Code Definition

> How the IRC 2009, IPC 2009 define fixture supply, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/fixture-supply/
- Last updated: 2026-09-07
- Data source: 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.

## Key facts

| Fact | Value |
| --- | --- |
| Defined in | IRC 2009, IPC 2009 (2009 editions transcribed in this corpus) |
| Primary source | IRC 2009 Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 5 (counted across the codes hosted here) |
| Wording identical across codes | No (compare before citing one code's wording under another) |

## Direct answer

Fixture supply is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “The water-supply pipe connecting a fixture or fixture fitting to a fixture branch.” The IPC 2009 words it differently, in Definitions: “The water supply pipe connecting a fixture to a branch water supply pipe or directly to a main water supply pipe.” 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 5 chapters of this corpus, most often in Water Supply and Distribution (IPC 2009), Definitions (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](https://nz.linkedin.com/in/barrington), Harth founder and architectural technology specialist · Published 2026-09-07 · Updated 2026-09-07.*

## What does this term mean?

**Fixture Supply** — IRC 2009, Definitions:

> The water-supply pipe connecting a fixture or fixture fitting to a fixture branch.

![Labeled code-term definition diagram: Fixture Supply: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/fixture-supply/diagram-1344.webp)

*How the IRC 2009, IPC 2009 define fixture supply, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

Two of the I-Codes in this corpus define **Fixture Supply**, and the wording is not identical — read the version that governs your question.

| Code | Where it is defined | Definition |
| --- | --- | --- |
| IRC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | The water-supply pipe connecting a fixture or fixture fitting to a fixture branch. |
| IPC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) | The water supply pipe connecting a fixture to a branch water supply pipe or directly to a main water supply pipe. |

## Where fixture supply is used in the code

The term appears in 5 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Water Supply and Distribution](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/water-supply-and-distribution.md) | IPC 2009 | 5 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | IRC 2009 | 3 |
| [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) | IPC 2009 | 2 |
| [Plumbing Fixtures](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/plumbing-fixtures.md) | IRC 2009 | 2 |
| [Water Supply and Distribution](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/water-supply-and-distribution.md) | IRC 2009 | 2 |

### The term in use

How the code actually writes about fixture supply, quoted from the 2009 text hosted here:

> The water distribution system shall be designed, and pipe sizes shall be selected such that under conditions of peak demand, the capacities at the fixture supply pipe outlets shall not be less than shown in Table 604.3.

— [IPC 2009 §604.3](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/water-supply-and-distribution.md)

> The bidet shall be equipped with either an air-gap-type or vacuum-breaker-type fixture supply fitting.

— [IRC 2009 §P2721.1](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/plumbing-fixtures.md)

> An individual shutoff valve shall be required on the fixture supply pipe to each plumbing fixture other than bathtubs and showers.

— [IRC 2009 §P2903.9.3](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/water-supply-and-distribution.md)


## The terms fixture supply is built out of

The definition above leans on 3 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what fixture supply covers:

- **[Fixture Branch](https://harth.build/resources/glossary/fixture-branch.md)** — IPC 2009: A drain serving two or more fixtures that discharges to another drain or to a stack.
- **[Fitting](https://harth.build/resources/glossary/fitting.md)** — IRC 2009: An accessory such as a locknut, bushing or other part of a wiring system that is intended primarily to perform a mechanical rather than an electrical function.
- **[Branch](https://harth.build/resources/glossary/branch.md)** — IRC 2009: Any part of the piping system other than a riser, main or stack.

## Fixture Supply: what to open, and in what order

Every row is a document this term depends on. The [ICC code library](https://codes.iccsafe.org/codes) and the [ICC adoption maps](https://www.iccsafe.org/advocacy/code-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 | Water Supply and Distribution (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | Plumbing Fixtures (IRC 2009) | |
| Confirm the dependent definition | Fixture Branch | |
| Confirm the dependent definition | Fitting | |
| Confirm the dependent definition | Branch | |
| 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](https://harth.build/resources/glossary.md)
- [Fixture Branch: Building Code Definition](https://harth.build/resources/glossary/fixture-branch.md)
- [Fitting: Building Code Definition](https://harth.build/resources/glossary/fitting.md)
- [Branch: Building Code Definition](https://harth.build/resources/glossary/branch.md)

## 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](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.

### Source links

- [codes.iccsafe.org](https://codes.iccsafe.org/codes)

- [iccsafe.org](https://www.iccsafe.org/advocacy/code-adoption-maps/)

## Frequently asked questions

### What is the code definition of fixture supply?

The International Residential Code (IRC) 2009 defines it in Definitions as: “The water-supply pipe connecting a fixture or fixture fitting to a fixture branch.” 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 fixture supply?

In this corpus the term is used across 5 chapters, led by Water Supply and Distribution 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 does Plumbing Code table 422.1 say about fixture count?

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 fixture supply, which the IRC 2009 defines as “The water-supply pipe connecting a fixture or fixture fitting to a fixture branch.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What is considered a plumbing fixture?

Plumbing Fixture is a separate defined term. The IRC 2009 defines it as: “A receptor or device that requires both a water-supply connection and a discharge to the drainage system, such as water closets, lavatories, bathtubs and sinks. Plumbing appliances as a special class of fixture are further defined.” That is not the same as fixture supply, which the IRC 2009 defines as “The water-supply pipe connecting a fixture or fixture fitting to a fixture branch.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What is a plumbing fixture supply line?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “The water-supply pipe connecting a fixture or fixture fitting to a fixture branch.” It is defined in IRC 2009, IPC 2009. It is not the same as Plumbing Fixture, which the IRC 2009 defines separately as “A receptor or device that requires both a water-supply connection and a discharge to the drainage system, such as water closets, lavatories, bathtubs and sinks. Plumbing appliances as a special class of fixture are further …” 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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