Section 508 vs ADA vs WCAG: what's the difference?
These three terms show up in the same sentence constantly, and it's easy to treat them as synonyms. They're not. One is a law. One is a federal procurement rule. One is a technical standard. Understanding which is which — and how they connect — makes every accessibility conversation with legal, procurement, or a buyer's security team much easier.
The short version
| Term | What it is | Who it applies to |
|---|---|---|
| WCAG | A technical standard published by the W3C — the actual success criteria that define what "accessible" means at a testable level. | Anyone building digital content; referenced by both laws below rather than being a law itself. |
| ADA (Title III) | A U.S. federal civil rights law covering "public accommodations," applied by courts to websites without one codified technical standard. | Private-sector businesses operating in the US, broadly. |
| Section 508 | A U.S. federal procurement requirement that explicitly incorporates WCAG 2.0 Level AA by reference (2018 refresh). | Federal agencies, and vendors selling to them. |
WCAG: the technical standard underneath both
The Web Content Accessibility Guidelines (WCAG) are published by the World Wide Web Consortium (W3C) and are the most widely recognized set of technical accessibility guidelines internationally. WCAG isn't a law — it's a testable specification: a list of success criteria organized under four principles (Perceivable, Operable, Understandable, Robust), each rated Level A, AA, or AAA. The current version, WCAG 2.2, has 55 success criteria at Level A and AA combined (31 at A, 24 at AA) — the two levels almost universally required by law, regulation, or contract. Level AA is the de facto commercial standard that both ADA settlement practice and Section 508 reference.
Neither ADA nor Section 508 invented their own separate technical rules — both point back to WCAG, just in different ways and with different legal force.
ADA: the general law, without a codified technical standard
Title III of the Americans with Disabilities Act prohibits discrimination on the basis of disability in "public accommodations" — a category courts have applied to commercial websites, especially those tied to a physical location or offering goods and services to the public. Unlike Section 508, ADA Title III does not have one codified technical standard for websites the way the EU's European Accessibility Act has EN 301 549. The Department of Justice (DOJ) has stated its long-standing position that Title III applies to websites, but has not finalized website-specific regulations.
In practice, that gap gets filled by case law and settlement patterns: U.S. courts and DOJ settlement agreements and consent decrees most commonly reference WCAG 2.0 or 2.1 Level AA as the de facto compliance benchmark. Committing to WCAG 2.2 AA — the current version of the standard — meets and exceeds that common practice and is a defensible, forward-looking position, even though it's informal legal practice shaped by litigation rather than a formal regulatory requirement.
Section 508: the federal procurement rule that names WCAG explicitly
Section 508 of the Rehabilitation Act requires federal agencies to make their electronic and information technology accessible — and it applies by extension to the vendors those agencies buy from. Unlike ADA Title III, Section 508's 2018 refresh is explicit: it incorporates WCAG 2.0 Level AA by reference. That's a meaningfully more direct, codified link to the WCAG technical standard than ADA has.
This is also why the VPAT (Voluntary Product Accessibility Template) — the document federal buyers and increasingly enterprise buyers ask vendors to fill out — has multiple editions. The WCAG Edition reports conformance directly against WCAG success criteria; the Revised Section 508 Edition uses 508's own chapter/table structure instead. For most SaaS and e-commerce vendors, the WCAG Edition is the right starting point, and it maps cleanly onto Section 508's 2018 refresh if a federal buyer later asks for that framing specifically.
What this means practically
If you're a SaaS or e-commerce vendor without federal buyers, ADA exposure from private litigation is your primary concern, and targeting WCAG 2.2 Level AA — the standard both frameworks ultimately point to — is the right technical bar to set. If a federal agency or a federal contractor is evaluating you, expect them to specifically ask about Section 508 conformance and likely request a VPAT. Either way, the underlying work is the same: audit against WCAG 2.2 A/AA success criteria, document honestly, and keep the audit current.
Do the underlying work once, use it for both
The AccessibleDocs Pro Kit is built around exactly this overlap: one WCAG 2.2 self-audit becomes the source of truth for your accessibility statement (ADA-facing), your VPAT (Section 508 and enterprise procurement-facing), and your remediation plan — so the three documents never drift apart or contradict each other.
One audit, every document a buyer might ask for
Pro Kit ($249) includes the VPAT 2.5 / ACR template, the enterprise questionnaire answer bank, and everything in Core — the WCAG 2.2 self-audit checklist, accessibility statement, remediation plan, and internal policy.
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Is WCAG 2.2 legally required?
Not directly by name in most cases — ADA Title III doesn't codify a specific WCAG version, and Section 508's 2018 refresh names WCAG 2.0 AA. But WCAG 2.2 AA is a superset that meets or exceeds both, which is why it's the recommended default target.
Do I need to worry about Section 508 if I don't sell to the federal government?
Not directly — Section 508 applies to federal agencies and their vendors. If you have no federal buyers, ADA Title III (and the EAA, if you serve EU consumers) are your primary legal exposure, and WCAG 2.2 AA is still the right technical target.
Is this legal advice?
No. This page and the linked templates are professional documentation resources, not legal advice, and using them does not create an attorney-client relationship. Have qualified counsel review your specific compliance posture, especially before responding to any legal demand or procurement requirement.