# Public Sewer: Building Code Definition

> How the IRC 2009 define public sewer, where the wording differs, and which chapters depend on the term.

- Canonical: https://harth.build/resources/glossary/public-sewer/
- 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 (2009 editions transcribed in this corpus) |
| Primary source | IRC 2009 Definitions (model text, not a jurisdiction's adopted text) |
| Chapters using the term | 10 (counted across the codes hosted here) |
| Wording identical across codes | Single code (compare before citing one code's wording under another) |

## Direct answer

Public sewer is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “A common sewer directly controlled by public authority.” 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 10 chapters of this corpus, most often in Sanitary Drainage (IPC 2009), Definitions (IPC 2009), General Regulations (IPC 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](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?

**Public Sewer** — IRC 2009, Definitions:

> A common sewer directly controlled by public authority.

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

*How the IRC 2009 define public sewer, where the wording differs, and which chapters depend on the term.*

## What must be verified before using this guidance?

**Public Sewer** is defined once in this corpus, in the [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) chapter of the International Residential Code (IRC) 2009:

> A common sewer directly controlled by public authority.

## Where public sewer is used in the code

The term appears in 10 chapters of the 2009 I-Codes hosted here. The chapters that lean on it hardest are the ones to read next.

| Chapter | Code | Mentions |
| --- | --- | --- |
| [Sanitary Drainage](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/sanitary-drainage.md) | IPC 2009 | 10 |
| [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) | IPC 2009 | 5 |
| [General Regulations](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/general-regulations.md) | IPC 2009 | 4 |
| [Definitions](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/definitions.md) | IRC 2009 | 4 |
| [Sanitary Drainage](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/sanitary-drainage.md) | IRC 2009 | 4 |
| [Traps, Interceptors and Separators](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/traps-interceptors-and-separators.md) | IPC 2009 | 3 |
| [Interior Environment](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/interior-environment.md) | IBC 2009 | 2 |
| [Storm Drainage](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/storm-drainage.md) | IPC 2009 | 2 |
| [Cesspools](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/cesspools.md) | IPC 2009 | 1 |
| [Plumbing Administration](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/plumbing-administration.md) | IRC 2009 | 1 |

### The term in use

How the code actually writes about public sewer, quoted from the 2009 text hosted here:

> Every building in which plumbing fixtures are installed and all premises having drainage piping shall be connected to a public sewer, where available, or an approved privatesewage disposal system in accordance with the International Private Sewage Disposal Code.

— [IPC 2009 §701.2](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/sanitary-drainage.md)

> Waste products from manufacturing or industrial operations shall not be introduced into the public sewer until it has been determined by the code official or other authority having jurisdiction that the introduction thereof will not damage the public sewersystem or interfere with the functioning of the sewage treatment plant.

— [IPC 2009 §302.2](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/general-regulations.md)

> and piping to the public sewer or private septic system.

— [IRC 2009 §P3001.1](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/sanitary-drainage.md)

## Public Sewer: 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 | |
| Re-check the requirement that uses it | Sanitary Drainage (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| Re-check the requirement that uses it | General Regulations (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IRC 2009) | |
| 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)
- [Building: Building Code Definition](https://harth.build/resources/glossary/building.md)
- [Construction Documents: Building Code Definition](https://harth.build/resources/glossary/construction-documents.md)
- [Registered Design Professional: Building Code Definition](https://harth.build/resources/glossary/registered-design-professional.md)
- [Dwelling Unit: Building Code Definition](https://harth.build/resources/glossary/dwelling-unit.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 public sewer?

The International Residential Code (IRC) 2009 defines it in Definitions as: “A common sewer directly controlled by public authority.” 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 public sewer?

In this corpus the term is used across 10 chapters, led by Sanitary 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 sewer?

Building Sewer is a separate defined term. The IRC 2009 defines it as: “That part of the drainage system that extends from the end of the building drain and conveys its discharge to a public sewer, private sewer, individual sewage-diSposal system or other point of disposal.” That is not the same as public sewer, which the IRC 2009 defines as “A common sewer directly controlled by public authority.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What is the minimum size of a building sewer to a public sewer?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “A common sewer directly controlled by public authority.” It is defined in IRC 2009. It is not the same as Building Sewer, which the IRC 2009 defines separately as “That part of the drainage system that extends from the end of the building drain and conveys its discharge to a public sewer, private sewer, individual sewage-diSposal system or other point of disposal.” 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 public sewer, which the IRC 2009 defines as “A common sewer directly controlled by public authority.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

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