# Contamination: Building Code Definition

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

- Canonical: https://harth.build/resources/glossary/contamination/
- 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 | 17 (counted across the codes hosted here) |
| Wording identical across codes | No (compare before citing one code's wording under another) |

## Direct answer

Contamination is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “An impairment of the quality of the potable water that creates an actual hazard to the public health through poisoning or through the spread of disease by sewage, industrial fluids or waste.” 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 17 chapters of this corpus, most often in Water Supply and Distribution (IPC 2009), Oxidizers, Oxidizing Gases and Oxidizing Cryogenic Fluids (IFC 2009), Flammable and Combustible Liquids (IFC 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?

**Contamination** — IRC 2009, Definitions:

> An impairment of the quality of the potable water that creates an actual hazard to the public health through poisoning or through the spread of disease by sewage, industrial fluids or waste.

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

*How the IRC 2009, IPC 2009 define contamination, 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 **Contamination**, 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) | An impairment of the quality of the potable water that creates an actual hazard to the public health through poisoning or through the spread of disease by sewage, industrial fluids or waste. |
| IPC 2009 | [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) | An impairment of the quality of the potable water that creates an actual hazard to the public health |

## Where contamination is used in the code

The term appears in 17 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 | 18 |
| [Oxidizers, Oxidizing Gases and Oxidizing Cryogenic Fluids](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/oxidizers-oxidizing-gases-and-oxidizing-cryogenic-fluids.md) | IFC 2009 | 6 |
| [Flammable and Combustible Liquids](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/flammable-and-combustible-liquids.md) | IFC 2009 | 5 |
| [Water Supply and Distribution](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/water-supply-and-distribution.md) | IRC 2009 | 5 |
| [Organic Peroxides](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/organic-peroxides.md) | IFC 2009 | 4 |
| [Special Construction](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/special-construction.md) | IBC 2009 | 3 |
| [Commercial Energy Efficiency](https://harth.build/resources/building-codes/us-states/maryland/iecc-2009/commercial-energy-efficiency.md) | IECC 2009 | 3 |
| [Duct Systems](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/duct-systems.md) | IMC 2009 | 3 |
| [Refrigeration](https://harth.build/resources/building-codes/us-states/new-hampshire/imc-2009/refrigeration.md) | IMC 2009 | 3 |
| [Use and Occupancy Classification](https://harth.build/resources/building-codes/us-states/maryland/ibc-2009/use-and-occupancy-classification.md) | IBC 2009 | 2 |
| [Flammable Finishes](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/flammable-finishes.md) | IFC 2009 | 2 |
| [Fixtures, Faucets and Fixture Fittings](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/fixtures-faucets-and-fixture-fittings.md) | IPC 2009 | 2 |

_5 further chapters mention the term._

### The term in use

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

> Surface bodies of water and land cisterns shall not be sources of individual water supply unless properly treated by approved means to prevent contamination.

— [IPC 2009 §602.3.1](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/water-supply-and-distribution.md)

> Liquid and solid oxidizers shall be stored in a manner to prevent contamination.

— [IFC 2009 §4004.1.9](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/oxidizers-oxidizing-gases-and-oxidizing-cryogenic-fluids.md)

> Vent piping for tanks storing Class I liquids shall not be manifolded with vent piping for tanks storing Class II and III liquids unless positive means are provided to prevent the vapors from Class I liquids from entering tanks storing Class II and III liquids, to prevent contamination and possible change in classification of less volatile liquid.

— [IFC 2009 §3404.2.7.3.5.3](https://harth.build/resources/building-codes/us-states/rhode-island/ifc-2009/flammable-and-combustible-liquids.md)


## The terms contamination 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 contamination covers:

- **[Potable Water](https://harth.build/resources/glossary/potable-water.md)** — IRC 2009: Water free from impurities present in amounts sufficient to cause disease or harmful physiological effects and conforming in bacteriological and chemical quality to the requirements of the public health authority havingjurisdiction.
- **[Sewage](https://harth.build/resources/glossary/sewage.md)** — IRC 2009: Any liquid waste containing animal matter, vegetable matter or other impurity in suspension or solution.
- **[Waste](https://harth.build/resources/glossary/waste.md)** — IRC 2009: Liquid-borne waste that is free of fecal matter.

## Contamination: 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 | Oxidizers, Oxidizing Gases and Oxidizing Cryogenic Fluids (IFC 2009) | |
| Re-check the requirement that uses it | Flammable and Combustible Liquids (IFC 2009) | |
| Re-check the requirement that uses it | Water Supply and Distribution (IRC 2009) | |
| Confirm the dependent definition | Potable Water | |
| Confirm the dependent definition | Sewage | |
| Confirm the dependent definition | Waste | |
| 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)
- [Potable Water: Building Code Definition](https://harth.build/resources/glossary/potable-water.md)
- [Sewage: Building Code Definition](https://harth.build/resources/glossary/sewage.md)
- [Waste: Building Code Definition](https://harth.build/resources/glossary/waste.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 contamination?

The International Residential Code (IRC) 2009 defines it in Definitions as: “An impairment of the quality of the potable water that creates an actual hazard to the public health through poisoning or through the spread of disease by sewage, industrial fluids or waste.” 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 contamination?

In this corpus the term is used across 17 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 is the definition of a building code?

Building is a separate defined term. The IBC 2009 defines it as: “Any structure used or intended for supporting or sheltering any use or occupancy.” That is not the same as contamination, which the IRC 2009 defines as “An impairment of the quality of the potable water that creates an actual hazard to the public health through poisoning or through the spread of disease by sewage, industrial fluids or waste.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.

### What is a definition of contamination?

In the 2009 I-Codes hosted here it is a defined term rather than a description. The IRC 2009 states, in Definitions: “An impairment of the quality of the potable water that creates an actual hazard to the public health through poisoning or through the spread of disease by sewage, industrial fluids or waste.” It is defined in IRC 2009, 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.

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