ADA Title II mandates WCAG 2.1 Level AA specifically. Not 2.0, not 2.2. Leovoid tests every one of the fifty applicable success criteria at that level, and this page explains what each principle covers and where public sector sites most commonly fail.
How WCAG is organised
WCAG is built from four principles, each containing guidelines, each containing testable success criteria. The four principles form the acronym POUR: Perceivable, Operable, Understandable, Robust. Every criterion carries a level of A, AA, or AAA. Level AA includes everything at A plus the AA criteria, which is what the law requires.
Level AAA is deliberately not a compliance target. The W3C itself states that AAA conformance is not achievable for all content, so treating it as a legal standard would be incoherent.
Principle 1: Perceivable
Information and interface components must be presentable to users in ways they can perceive. If a user cannot receive the information at all, nothing else matters.
Text alternatives
Every non text element needs a text equivalent. Decorative images take an empty alt attribute so screen readers skip them; informative images need alt text that conveys the same information the image does. Complex images such as charts need a longer description somewhere accessible.
The most common failure is not missing alt text but useless alt text. An attribute reading image, photo, or the original filename passes an automated check and fails a real user completely.
Time based media
Prerecorded video needs captions and an audio description. Prerecorded audio needs a transcript. Live video needs live captions at AA. For a municipality streaming council meetings, this is frequently the single largest compliance gap, and it is rarely caught by automated tooling because the scanner cannot judge whether captions are accurate or merely present.
Adaptable content
Content must survive being presented differently without losing information or structure. Reading order must make sense when styling is stripped. Instructions must not rely solely on shape, colour, size, or position, so round button on the right fails while Submit button fails less.
Under 2.1, content must also reflow to a 320 pixel viewport width without horizontal scrolling, and must remain functional in both orientations unless a specific orientation is essential.
Distinguishable
Normal text requires a contrast ratio of at least 4.5 to 1 against its background. Large text, defined as 18 point or 14 point bold, requires 3 to 1. Under 2.1, user interface components and meaningful graphics also require 3 to 1, which catches a great many form field borders and icon buttons that previously passed.
Text must be resizable to 200 percent without loss of content or function, and users must be able to override text spacing without breaking the layout.
Principle 2: Operable
Interface components and navigation must be operable. Perceiving content is useless if you cannot act on it.
Keyboard accessible
All functionality must be available from a keyboard alone, with no keyboard traps. This is the criterion that most reliably separates sites that were tested from sites that were not. Custom dropdowns, modal dialogs, carousels, and drag and drop interfaces are the usual offenders.
Test it yourself in two minutes: put your mouse away and tab through the page. If you cannot reach something, cannot escape something, or cannot see where you are, you have found a real barrier.
Enough time
Time limits must be adjustable, extendable, or removable, with narrow exceptions for real time events and genuine security constraints. Session timeouts on government forms are a recurring problem: a user with a motor impairment filling in a lengthy permit application may legitimately need three times the assumed duration.
Moving, blinking, or auto updating content lasting more than five seconds must be pausable.
Seizures and physical reactions
Nothing may flash more than three times per second. This is short, absolute, and non negotiable, because the consequence of violating it is a medical event rather than an inconvenience.
Navigable
Pages need descriptive titles, a mechanism to skip repeated blocks such as a skip link, a logical focus order, link text that makes sense out of context, multiple ways to locate a page, descriptive headings and labels, and a visible focus indicator.
Click here as link text fails this. So does removing focus outlines in CSS because they were considered unattractive, which remains distressingly common.
Input modalities
Added in 2.1. Functionality operated by complex gestures must have a single pointer alternative. Actions must not complete on the down event, so a user who presses the wrong control can move away before releasing. Where a control has visible text, its accessible name must contain that text, which matters enormously for voice control users.
Principle 3: Understandable
Information and interface operation must be understandable. Content that is perceivable and operable can still be unusable if it is incomprehensible or behaves unpredictably.
Readable
The language of the page must be programmatically set, and any passage in a different language must be marked up as such. Without this, a screen reader will pronounce French text using English phonetics, producing something close to noise.
Predictable
Focusing an element must not trigger a change of context. Changing a setting must not automatically submit a form or navigate away unless the user has been warned. Navigation must appear in a consistent order across pages, and components with the same function must be identified consistently.
Input assistance
Errors must be identified in text, not by colour alone. Labels or instructions must be provided where input is expected. Error suggestions must be offered where the system can infer one. For legal, financial, or data modifying submissions, the action must be reversible, checked, or confirmed.
A red border with no accompanying text is the classic failure here, and it fails for far more people than just those who cannot distinguish red.
Principle 4: Robust
Content must be robust enough to be interpreted reliably by a wide variety of user agents, including assistive technologies.
Compatible
Markup must parse cleanly, with no duplicate IDs and no improperly nested elements. Every user interface component must expose a correct name, role, and value to assistive technology. Under 2.1, status messages must be programmatically announced without moving focus, which is what ARIA live regions exist for.
Most robustness failures come from custom components built with generic div and span elements plus click handlers. A div is not a button, however convincingly it has been styled to look like one.
Where public sector sites actually fail
Across the audits Leovoid has run, failures cluster tightly. Contrast issues appear on nearly every site. Missing or unhelpful form labels are close behind. Keyboard traps in custom widgets, absent or broken skip links, meaningless link text, PDFs that were never tagged, and video without accurate captions round out the list.
Almost none of these are difficult to fix. They persist because nobody has looked.
Conformance is not the same as usable
A site can satisfy every AA criterion and still be exhausting to use with a screen reader. Conformance is a floor established so that obligations can be tested and enforced, not a description of a good experience. The most useful question is not whether the site passes, but whether someone using assistive technology can actually complete the task they came to do.