Section 508 is the part of the Rehabilitation Act that requires U.S. federal agencies to make their electronic content — including PDFs — accessible to people with disabilities. If your agency publishes a PDF, or your company sells documents or software to the federal government, that PDF generally has to meet WCAG 2.0 Level A and AA, the standard Section 508 adopts by reference. This guide explains what the law covers, who has to comply, exactly what it demands of a PDF, and how those PDFs get tested before they reach the public.
This is general information, not legal advice.
What Section 508 actually is
Section 508 is a 1998 amendment to the Rehabilitation Act of 1973. The Rehabilitation Act was the first major U.S. federal disability rights law, and Section 508 added a specific obligation: when federal agencies develop, procure, maintain, or use information and communication technology (ICT), that technology must be accessible to people with disabilities — both members of the public and federal employees.
PDFs sit squarely inside that definition. A benefits form, a public report, a tax document, a grant notice, a fact sheet — all are "electronic content" that the public is expected to read, complete, or rely on. Section 508 says those documents have to work for someone using a screen reader, navigating by keyboard, or relying on high-contrast or magnified views.
It helps to separate two related ideas at the outset:
- Section 508 is the legal requirement — the "you must do this" coming from federal law.
- WCAG and PDF/UA are the technical standards — the "here's how" that define what an accessible document looks like in practice.
Section 508 leans on WCAG for the rules and, in the document world, on the PDF/UA standard (ISO 14289) for how accessibility is implemented inside the file itself. We cover that distinction in depth in our WCAG and PDF/UA accessible-PDF guide.
Who has to comply with Section 508
Two groups are affected, and the second one surprises people.
Federal agencies. Every executive-branch federal agency is directly bound by Section 508. Their public-facing PDFs, internal documents used by employees, and the ICT they buy all fall under the standard. This includes departments, independent agencies, and the offices within them.
Federal contractors and vendors — through procurement. Section 508 is not a regulation that private companies must follow simply because they exist. It reaches the private sector through the buying process. When an agency procures software, a website build, a document-conversion service, or content itself, federal acquisition rules require that what the agency buys conforms to Section 508. So if you want to sell to the government, your deliverables have to meet the standard — and you'll typically be asked to prove it in writing.
That proof usually takes the form of an Accessibility Conformance Report. If you're a vendor, the practical mechanics matter more than the statute, and we walk through them in Federal contractor PDF requirements.
Note that Section 508 binds federal agencies. State and local governments are generally governed by the ADA (Title II) rather than Section 508 — though many adopt 508 voluntarily, and some state laws ("little 508s") mirror it. The relationship between these overlapping laws is its own topic, covered in Section 508 vs. Section 504 and below.
The Revised 508 Standards and WCAG 2.0 AA
For nearly two decades, Section 508 had its own bespoke list of technical rules. That changed with the Revised 508 Standards — often called the "508 Refresh" — which the U.S. Access Board finalized in 2017, with a compliance date in January 2018.
The Refresh did something important: instead of maintaining a separate set of rules, it incorporated WCAG 2.0 Level A and AA by reference. From that point forward, conforming to the relevant WCAG 2.0 A and AA success criteria is how you conform to Section 508 for web content and electronic documents. This also harmonized U.S. federal requirements with the international standard, EN 301 549, which references WCAG as well.
Two practical consequences flow from this:
- The technical bar for a PDF is WCAG 2.0 A and AA — things like meaningful structure, alternative text, correct reading order, and sufficient color contrast.
- Functional performance criteria also apply. These are outcome-based requirements: the content must be usable without vision, without hearing, with limited reach or strength, with limited cognition, and so on. They act as a backstop — if a technical checklist passes but a real person still can't use the document, the functional criteria are not met.
One detail trips people up: Section 508 still references WCAG 2.0, not the newer 2.1 or 2.2. That's a deliberate consequence of how the standard was written and when. We unpack why that's the case, and how it interacts with newer rules, in the Section 508 Refresh and Revised Standards.
What Section 508 requires for a PDF, specifically
WCAG was written with web pages in mind, so it helps to translate the relevant criteria into concrete PDF requirements. An accessible PDF under Section 508 needs the following.
| Requirement | What it means for a PDF | Why it matters |
|---|---|---|
| Tagged structure | The document has a proper tag tree (headings, paragraphs, lists) rather than being a bag of loose text | Screen readers use tags to convey document structure and navigation |
| Logical reading order | Content is read back in the order a sighted person would read it | Without it, a screen reader may jumble columns, captions, and headers |
| Alternative text | Every meaningful image, chart, and figure has a text description; decorative images are marked as artifacts | A non-visual user gets the information the image conveys |
| Document language | The PDF declares its primary language (and any passages in another language) | The screen reader uses correct pronunciation |
| Headings and navigation | Real heading tags and, for longer documents, bookmarks | Users can jump through the document instead of reading linearly |
| Accessible tables | Tables use table tags with identified header cells | Cell data is announced with its row/column context |
| Accessible forms | Form fields are tagged, labeled, and in a logical tab order | Users can complete forms by keyboard and screen reader |
| Sufficient color contrast | Text meets WCAG 2.0 AA contrast ratios; color is not the only way meaning is conveyed | Low-vision and color-blind users can read the content |
| Document title and metadata | A descriptive title set in document properties, shown in the window/tab | Users can tell which document they're in |
Two foundational pieces — tags and reading order — are worth their own deep dive, in PDF tags and reading order, since almost every other requirement depends on them being correct.
It's also worth naming what Section 508 does not require. A document doesn't have to be visually plain or boring to be accessible. The goal is parity of access: someone using assistive technology gets the same information, in a usable form, as everyone else.
How PDFs are tested for Section 508 conformance
There's no single button that proves a PDF is compliant. Real-world testing combines three layers, because each catches things the others miss.
1. Automated checking
Automated tools scan the file's structure and flag machine-detectable problems — missing tags, images without alt text, no document title, no language set, table cells lacking headers. Tools range from the checker built into Adobe Acrobat to dedicated platforms (this is exactly the kind of scanning PDF Compliance automates at scale).
Automation is fast and catches a lot, but it has a hard ceiling: a tool can tell you alt text exists, but not whether it's accurate. It can confirm a reading order is defined, but not whether that order makes sense to a human. Industry guidance generally holds that automated tools catch only a portion of accessibility issues on their own — the rest needs human judgment.
2. The Matterhorn Protocol
The Matterhorn Protocol, published by the PDF Association, is the structured bridge between "test the file" and "test against the standard." It breaks PDF/UA conformance into a defined set of failure conditions and checkpoints, and labels each as machine-checkable, human-checkable, or both. Testers and tools use it as a consistent rubric so that "we checked this PDF" means the same thing from one reviewer to the next, rather than an ad-hoc once-over.
3. Manual screen-reader testing
The final layer is opening the document with assistive technology — a screen reader such as NVDA, JAWS, or VoiceOver, plus keyboard-only navigation — and experiencing it the way a disabled user would. This is where you catch the issues automation can't: alt text that's technically present but useless ("image1.png"), a reading order that's defined but illogical, a form that tabs in the wrong sequence. For anything published to the public under Section 508, manual verification is the difference between "probably fine" and "actually usable."
If a document fails these checks, it has to be remediated — corrected so it conforms. We cover that process end to end in how to remediate an inaccessible PDF.
VPATs and ACRs: proving conformance in procurement
For agencies, accessibility is mostly an internal publishing discipline. For vendors, it becomes a paperwork-and-procurement exercise — and the key document is the VPAT.
A VPAT (Voluntary Product Accessibility Template) is a standardized form, published by the Information Technology Industry Council (ITI), that documents how a product or piece of content measures up against accessibility standards, criterion by criterion. Once you fill it out for a specific product, the completed document is properly called an Accessibility Conformance Report (ACR).
VPATs come in editions so you can report against the right standard:
| VPAT edition | Reports conformance against |
|---|---|
| WCAG | The W3C WCAG success criteria |
| Section 508 | The Revised 508 Standards (WCAG 2.0 A/AA + 508-specific provisions) |
| EN 301 549 | The European ICT accessibility standard |
| INT | A combined report covering all of the above |
When a federal agency evaluates bids, the ACR is how they compare vendors' accessibility claims on a like-for-like basis — and how a vendor demonstrates good faith. A thorough, honest ACR (including frank notes on partial support) is far more credible than one that claims flawless conformance everywhere. We dig into how to fill one out for documents specifically in VPAT and ACR for PDF documents.
How Section 508 relates to Section 504 and the ADA
Section 508 doesn't operate alone. Three federal laws overlap, and PDFs can fall under more than one at once.
- Section 508 (Rehabilitation Act): governs the ICT and electronic content of federal agencies (and reaches contractors via procurement). Technical bar: WCAG 2.0 A/AA.
- Section 504 (Rehabilitation Act): a broader nondiscrimination mandate covering programs that receive federal funding — universities, hospitals, many nonprofits. The relevant HHS rule (published May 9, 2024) sets a WCAG 2.1 AA bar for the web and mobile content of HHS-funded recipients. So a federally funded organization may be on the hook even though it isn't a federal agency.
- The ADA (Americans with Disabilities Act): governs state and local governments (Title II) and private places of public accommodation (Title III). The 2024 DOJ Title II rule adopts WCAG 2.1 AA for government web content and conventional electronic documents, with phased deadlines in 2027 and 2028.
The headline takeaway: which law applies depends on who you are, and the technical bar isn't identical across them (508 references 2.0; the newer 504 and Title II rules reference 2.1). A safe practical strategy for any organization touching multiple regimes is to build to the newer, stricter target. We compare two of these regimes directly in Section 508 vs. Section 504.
Key takeaways
- Section 508 requires U.S. federal agencies to make their ICT and electronic content — including PDFs — accessible, and reaches contractors and vendors through federal procurement.
- The Revised 508 Standards (the "508 Refresh," effective January 2018) adopt WCAG 2.0 Level A and AA by reference, plus functional performance criteria; Section 508 still references 2.0, not the newer 2.1/2.2.
- For a PDF, that means tagged structure, logical reading order, alt text, declared language, accessible tables and forms, sufficient contrast, and a real document title.
- Conformance is verified in layers: automated checking, the Matterhorn Protocol, and manual screen-reader testing — no single tool proves compliance on its own.
- Vendors document conformance in a VPAT, which once completed is an Accessibility Conformance Report (ACR) used to compare bids in procurement.
Frequently asked questions
What standard does Section 508 require for PDFs?+
The Revised 508 Standards (effective 2018) incorporate WCAG 2.0 Level A and AA by reference and apply them to electronic documents, including PDFs.
Who has to comply with Section 508?+
Federal agencies and, through procurement and funding requirements, the vendors and contractors that supply them with electronic content and IT.
