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Standards

Section 508 (WCAG 2.0 Level AA)

Section 508 (WCAG 2.0 Level AA) covers 37 Level A and AA success criteria. US federal procurement. The 2017 refresh of Section 508 incorporates WCAG 2.0 AA.

Last reviewed September 2026

WCAG 2.0 includes 4.1.1 Parsing, which was later declared obsolete and removed in 2.2 because modern browsers and assistive technology no longer depend on it. It is treated as satisfied and is not evaluated.

All 37 success criteria

Each one is a separate row in a conformance report, with its own judgement and its own remarks. This is the list Affido reports against when you select Section 508.

1. Perceivable (14)

1.1.1Non-text ContentLevel A
Every image, icon, chart and control needs a text alternative that conveys the same purpose. Presence of an alt attribute is not conformance — judge whether the text actually describes the function or content. Filenames, 'image', 'photo', repeated link text and empty alt on meaningful images all fail.
1.2.1Audio-only and Video-only (Prerecorded)Level A
Prerecorded audio-only needs a transcript; video-only needs an audio description or text alternative.
1.2.2Captions (Prerecorded)Level A
All prerecorded video with audio needs synchronised captions. Auto-generated captions that are not reviewed generally do not meet this.
1.2.3Audio Description or Media Alternative (Prerecorded)Level A
Prerecorded video needs either an audio description track or a full text alternative for the visual information.
1.2.4Captions (Live)Level AA
Live audio in synchronised media needs real-time captions. Not applicable if the product has no live media.
1.2.5Audio Description (Prerecorded)Level AA
Prerecorded video needs an audio description track (the text-alternative escape of 1.2.3 is not available at AA).
1.3.1Info and RelationshipsLevel A
Structure conveyed visually must exist in markup: real headings in a sensible hierarchy, real lists, real table headers, labels programmatically tied to inputs, fieldset/legend for grouped controls. Styled divs that look like headings fail.
1.3.2Meaningful SequenceLevel A
DOM order must match the meaningful reading order. CSS reordering (flex/grid order, absolute positioning) that desynchronises visual and DOM order fails.
1.3.3Sensory CharacteristicsLevel A
Instructions must not rely solely on shape, colour, size, or position — 'click the green button on the right' fails.
1.4.1Use of ColorLevel A
Colour must not be the only way information is conveyed — required-field asterisks in red only, error states that only change border colour, status dots without text labels, and links in body text distinguished only by colour all fail.
1.4.2Audio ControlLevel A
Audio that plays automatically for more than 3 seconds needs a pause/stop or independent volume control.
1.4.3Contrast (Minimum)Level AA
Text needs 4.5:1 contrast (3:1 for large text). Automated measurement is reliable except over images or gradients.
1.4.4Resize TextLevel AA
Text must scale to 200% without loss of content or function. Fixed-height containers with overflow:hidden and viewport meta tags blocking zoom fail.
1.4.5Images of TextLevel AA
Text rendered as an image fails unless the presentation is essential (logos are exempt). Look for headings, banners and pricing tables shipped as images.

2. Operable (12)

2.1.1KeyboardLevel A
Every function must work from the keyboard. div/span click handlers without tabindex and key handlers, custom dropdowns, drag-only interactions and canvas widgets are the usual failures.
2.1.2No Keyboard TrapLevel A
Keyboard focus must be able to leave every component. Modals, embedded media players and third-party widgets are the usual risk.
2.2.1Timing AdjustableLevel A
Time limits (session timeouts, checkout holds, carousels that advance) must be adjustable, extendable or disableable. A 20-hour-plus limit is exempt.
2.2.2Pause, Stop, HideLevel A
Content that moves, blinks, scrolls or auto-updates for more than 5 seconds needs a pause control. Hero carousels and marquees are the usual failure.
2.3.1Three Flashes or Below ThresholdLevel A
Nothing may flash more than three times per second above the general/red flash thresholds.
2.4.1Bypass BlocksLevel A
A skip link, landmark regions or a heading structure must let users bypass repeated navigation.
2.4.2Page TitledLevel A
Each page needs a title that describes its topic or purpose. Identical titles across pages, or a bare brand name, fail.
2.4.3Focus OrderLevel A
Focus order must preserve meaning and operability. Positive tabindex values, modals that do not move focus, and content appended at the end of the DOM but shown at the top are the usual failures.
2.4.4Link Purpose (In Context)Level A
Link purpose must be determinable from the link text plus its context. 'Click here', 'read more', 'learn more' and bare URLs repeated across a page fail. This is the single most common AI-detectable failure.
2.4.5Multiple WaysLevel AA
More than one way to locate a page: navigation plus search, a sitemap, or an index. Exempt if the page is a step in a process.
2.4.6Headings and LabelsLevel AA
Headings and labels must describe topic or purpose. A present-but-vague label ('Input', 'Field 1', 'Section') fails even though automated tools see a label.
2.4.7Focus VisibleLevel AA
Keyboard focus must have a visible indicator. `outline: none` without a replacement is the usual failure.

3. Understandable (10)

3.1.1Language of PageLevel A
The html element needs a valid lang attribute.
3.1.2Language of PartsLevel AA
Passages in another language need their own lang attribute.
3.2.1On FocusLevel A
Receiving focus must not trigger a change of context — no auto-submit or navigation on focus.
3.2.2On InputLevel A
Changing a setting must not automatically change context unless the user was warned. Selects that navigate on change are the usual failure.
3.2.3Consistent NavigationLevel AA
Repeated navigation must appear in the same relative order across pages.
3.2.4Consistent IdentificationLevel AA
Components with the same function must be identified consistently across pages — a 'Search' button that is 'Find' elsewhere fails.
3.3.1Error IdentificationLevel A
Errors must be identified in text and described to the user, not signalled by colour alone.
3.3.2Labels or InstructionsLevel A
Inputs need labels or instructions. Placeholder-only labelling fails because the text disappears on entry.
3.3.3Error SuggestionLevel AA
When an error is detected and a correction is known, suggest it. 'Invalid input' with no guidance fails.
3.3.4Error Prevention (Legal, Financial, Data)Level AA
Submissions with legal or financial consequence must be reversible, checked, or confirmable.

4. Robust (1)

4.1.2Name, Role, ValueLevel A
Custom controls need a correct accessible name, role and state exposed to assistive technology.

What Section 508 does not cover

18 criteria were added to WCAG after this standard’s reference version. A buyer asking for Section 508 today is likely to ask for WCAG 2.2 eventually, so they are worth knowing about even when they are out of scope:

  • 1.3.4 Orientation (added in WCAG 2.1)
  • 1.3.5 Identify Input Purpose (added in WCAG 2.1)
  • 1.4.10 Reflow (added in WCAG 2.1)
  • 1.4.11 Non-text Contrast (added in WCAG 2.1)
  • 1.4.12 Text Spacing (added in WCAG 2.1)
  • 1.4.13 Content on Hover or Focus (added in WCAG 2.1)
  • 2.1.4 Character Key Shortcuts (added in WCAG 2.1)
  • 2.4.11 Focus Not Obscured (Minimum) (added in WCAG 2.2)
  • 2.5.1 Pointer Gestures (added in WCAG 2.1)
  • 2.5.2 Pointer Cancellation (added in WCAG 2.1)
  • 2.5.3 Label in Name (added in WCAG 2.1)
  • 2.5.4 Motion Actuation (added in WCAG 2.1)
  • 2.5.7 Dragging Movements (added in WCAG 2.2)
  • 2.5.8 Target Size (Minimum) (added in WCAG 2.2)
  • 3.2.6 Consistent Help (added in WCAG 2.2)
  • 3.3.7 Redundant Entry (added in WCAG 2.2)
  • 3.3.8 Accessible Authentication (Minimum) (added in WCAG 2.2)
  • 4.1.3 Status Messages (added in WCAG 2.1)

Other standards

  • WCAG 2.2 Level AA — 55 criteria. The current version of the guidelines, and the safest answer when a buyer does not name one.
  • WCAG 2.1 Level AA — 49 criteria. What HECVAT asks about by name, and what the ADA Title II rule requires of state and local government.
  • EN 301 549 (WCAG 2.1 Level AA) — 49 criteria. European public procurement, and the reference point for the European Accessibility Act.

Affido always evaluates against WCAG 2.2 and reports against whichever standard your buyer asked for, so one scan answers every version of the question.

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Section 508 (WCAG 2.0 Level AA): the 37 criteria, and who asks for it · Affido