Building Code Glossary
Individual Water Supply: Building Code Definition
How the IRC 2009, IPC 2009 define individual water supply, 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
Individual water supply is a defined term in the International Residential Code (IRC) 2009, in Definitions. The code's own words are: “A supply other than an approvedpublic water supply that serves one or more families.” The IPC 2009 words it differently, in Definitions: “A water supply that serves one or more families, and that is not an approved public water supply.” 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 6 chapters of this corpus, most often in Water Supply and Distribution (IPC 2009), General Plumbing Requirements (IRC 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.
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?
Individual Water Supply — IRC 2009, Definitions:
A supply other than an approvedpublic water supply that serves one or more families.
What must be verified before using this guidance?
Two of the I-Codes in this corpus define Individual Water Supply, and the wording is not identical — read the version that governs your question.
| Code | Where it is defined | Definition |
|---|---|---|
| IRC 2009 | Definitions | A supply other than an approvedpublic water supply that serves one or more families. |
| IPC 2009 | Definitions | A water supply that serves one or more families, and that is not an approved public water supply. |
Where individual water supply is used in the code
The term appears in 6 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 | IPC 2009 | 17 |
| General Plumbing Requirements | IRC 2009 | 4 |
| General Regulations | IPC 2009 | 2 |
| Definitions | IPC 2009 | 1 |
| Definitions | IRC 2009 | 1 |
| Water Supply and Distribution | IRC 2009 | 1 |
The term in use
How the code actually writes about individual water supply, quoted from the 2009 text hosted here:
This chapter shall govern the materials, design and installation of water supply systems, both hot and cold, for utilization in connection with human occupancy and habitation and shall govern the installation of individual water supply systems.
When either a public water-supply or sewer system, or both, are not available, or connection to them is not feasible, an individual water supply or individual (private) sewage-disposal system, or both, shall be provided.
Cross-connections between an individual water supply and a potable public water supply shall be prohibited.
The terms individual water supply is built out of
The definition above leans on 1 other defined term. Each carries its own code definition, and a local amendment to any of them changes what individual water supply covers:
- Approved — IBC 2009: Acceptable to the code official or authority having jurisdiction.
Individual Water Supply: 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 | Water Supply and Distribution (IPC 2009) | |
| Re-check the requirement that uses it | General Plumbing Requirements (IRC 2009) | |
| Re-check the requirement that uses it | General Regulations (IPC 2009) | |
| Re-check the requirement that uses it | Definitions (IPC 2009) | |
| 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
- Approved: Building Code Definition
- Building: Building Code Definition
- Construction Documents: Building Code Definition
- Registered Design Professional: 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 individual water supply?
The International Residential Code (IRC) 2009 defines it in Definitions as: “A supply other than an approvedpublic water supply that serves one or more families.” 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 individual water supply?
In this corpus the term is used across 6 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 a potable water supply?
Potable Water is a separate defined term. The IRC 2009 defines it as: “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.” That is not the same as individual water supply, which the IRC 2009 defines as “A supply other than an approvedpublic water supply that serves one or more families.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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 individual water supply, which the IRC 2009 defines as “A supply other than an approvedpublic water supply that serves one or more families.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted.
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