# Concealed Fouling Surface: Building Code Definition > How the IPC 2009 define concealed fouling surface, where the wording differs, and which chapters depend on the term. - Canonical: https://harth.build/resources/glossary/concealed-fouling-surface/ - 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 | IPC 2009 (2009 editions transcribed in this corpus) | | Primary source | IPC 2009 Definitions (model text, not a jurisdiction's adopted text) | | Chapters using the term | 3 (counted across the codes hosted here) | | Wording identical across codes | Single code (compare before citing one code's wording under another) | ## Direct answer Concealed fouling surface is a defined term in the International Plumbing Code (IPC) 2009, in Definitions. The code's own words are: “Any surface of a plumbing fixture which is not readily visible and is not scoured or cleansed with each fixture operation.” 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 3 chapters of this corpus, most often in Fixtures, Faucets and Fixture Fittings (IPC 2009), Plumbing Fixtures (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. 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? **Concealed Fouling Surface** — IPC 2009, Definitions: > Any surface of a plumbing fixture which is not readily visible and is not scoured or cleansed with each fixture operation. ![Labeled code-term definition diagram: Concealed Fouling Surface: Building Code Definition](https://efwwel0vyt9vy5so.public.blob.vercel-storage.com/images/glossary/concealed-fouling-surface/diagram-1344.webp) *How the IPC 2009 define concealed fouling surface, where the wording differs, and which chapters depend on the term.* ## What must be verified before using this guidance? **Concealed Fouling Surface** is defined once in this corpus, in the [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) chapter of the International Plumbing Code (IPC) 2009: > Any surface of a plumbing fixture which is not readily visible and is not scoured or cleansed with each fixture operation. ## Where concealed fouling surface is used in the code The term appears in 3 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](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/fixtures-faucets-and-fixture-fittings.md) | IPC 2009 | 2 | | [Plumbing Fixtures](https://harth.build/resources/building-codes/us-states/maryland/irc-2009/plumbing-fixtures.md) | IRC 2009 | 2 | | [Definitions](https://harth.build/resources/building-codes/us-states/new-hampshire/ipc-2009/definitions.md) | IPC 2009 | 1 | ## The terms concealed fouling surface is built out of The definition above leans on 2 other defined terms. Each carries its own code definition, and a local amendment to any of them changes what concealed fouling surface covers: - **[Plumbing Fixture](https://harth.build/resources/glossary/plumbing-fixture.md)** — IRC 2009: 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](https://harth.build/resources/glossary/plumbing.md)** — IRC 2009: For the purpose of this code, plumbing refers to those installations, repairs, maintenance and alterations regulated by Chapters 25 through 33. ## Concealed Fouling Surface: 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 IPC | Definitions | | | Re-check the requirement that uses it | Fixtures, Faucets and Fixture Fittings (IPC 2009) | | | Re-check the requirement that uses it | Plumbing Fixtures (IRC 2009) | | | Re-check the requirement that uses it | Definitions (IPC 2009) | | | Confirm the dependent definition | Plumbing Fixture | | | Confirm the dependent definition | Plumbing | | | 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) - [Plumbing Fixture: Building Code Definition](https://harth.build/resources/glossary/plumbing-fixture.md) - [Plumbing: Building Code Definition](https://harth.build/resources/glossary/plumbing.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 concealed fouling surface? The International Plumbing Code (IPC) 2009 defines it in Definitions as: “Any surface of a plumbing fixture which is not readily visible and is not scoured or cleansed with each fixture operation.” 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 concealed fouling surface? In this corpus the term is used across 3 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 are the plumbing code requirements for fixtures? 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 concealed fouling surface, which the IPC 2009 defines as “Any surface of a plumbing fixture which is not readily visible and is not scoured or cleansed with each fixture operation.” — read both before applying either, and confirm the wording in the edition your jurisdiction has adopted. --- - Continue in Harth (open this topic in the Harth agent): https://app.harth.build/agent?context=%2Fresources%2Fglossary%2Fconcealed-fouling-surface%2F - View this page in a browser: https://harth.build/resources/glossary/concealed-fouling-surface/ - All resources for agents: https://harth.build/llms.txt