A Guide to Web Accessibility in the US

You've decided to make your website accessible to people with disabilities. Now what? The first thing you need to know is that there are two web accessibility standards which are used: WCAG 2.0 and Section 508. This guide will explain what each of the web accessibility standards is, the differences between them, which to use, and the levels of web accessibility. Let's get started!


The World Wide Web Consortium (W3C) is the leading group which sets international standards for the web. In 1997 they launched a project called the Web Accessibility Initiative (WAI). Two years later, they released the Web Content Accessibility Guidelines (WCAG). The guidelines apply not just to websites but also to devices like cell phones. WCAG became the de facto standard and is used by many countries.

In 2008, the WAI updated the standards by publishing the WCAG 2.0. These standards replaced the previous standards of WCAG 1.0.

WCAG 2.0 has four principles which state that websites must be perceivable, operable, understandable, and robust. There are a total of 12 guidelines under each of these principles. In order to make sure a website is meeting these guidelines, there are a total of 61 testable “success criteria.” Here is how it looks:
  • Web accessibility principle
    • Web accessibility guideline
      • Testable success criteria
You can use tools like Monsido's accessibility checker to see whether your web pages are passing or failing each of the testable success criteria. Note, however, that some of the tests aren’t as simple as pass/fail. Some tests require a human check to make sure the website meets the guideline.

For example:

One of the guidelines under the “perceivable” principle is that websites should, “Provide text alternatives for any non-text content so that it can be changed into other forms people need, such as large print, braille, speech, symbols or simpler language.”

If you do not have Alt tags for images, then the test will come back as an error. However, not all images need Alt tags – such as when the image is purely decorative. A human check would show that the image actually doesn’t need a text alternative to make the web content perceivable.

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The Levels of Web Accessibility

There are three levels of web accessibility established under WCAG 2.0. Level A is the least strict and the level which most closely resembles Section 508. Level AAA is very strict. For example, to be in compliance with AAA standards, your website would need to have a prerecorded sign language interpretation for all prerecorded audio in media. You have probably seen this on TV broadcasts of important government announcements; the interpreter is shown in a small box in the corner of the screen.

If you meet level AA, it means that you meet all of the criteria of level A and level AA. If you meet level AAA, it means meeting the criteria of levels A, AA, and AAA.

It is very difficult to always be in compliance with level AAA. Most companies and organizations worrying about accessibility should strive for level AA. At this level, they will be legally compliant in most countries, can avoid lawsuits, and provide a good experience for all users.

Learn about Monsido's web accessibility tool here

Americans With Disabilities Act (ADA)

The American with Disabilities Act (ADA) was enforced to ensure equal opportunity for people with disabilities through the establishment of design standards for the construction and alteration of facilities in the built environment. ADA compliance relates to areas of public life including jobs, school, transportation, and all public and private places that are open to the general public, whereby discrimination against individuals with disabilities is strictly prohibited. Although meant to cover physical access barriers, new lawsuits under the act have expanded the definition of areas of public accommodation to include websites and online applications. While there are no set legal guidelines in place for web accessibility under the ADA, the WCAG 2.0 level AA is used as a standard for reference.

Due to this new understanding of the scope of the ADA, there has been a spike in ADA lawsuits for various websites across the US. To learn about what you can do if you end up with an ADA demand letter and an impending lawsuit, read our guide on how to address this matter appropriately. 

Section 508

Federal agencies in the United States are required to comply with Section 508 of the Rehabilitation Act. Section 508 relates to government information and communications technology and addresses the requirements of all federal agencies to make their electronic documents and information accessible to those with impairments or disabilities. A recent refresh of this law moved to have conformance reflect the criteria from the WCAG 2.0 AA standard which meant that all web content, digital documents, and software should at minimum adhere to WCAG 2.0 Level AA to be compliant under Section 508.

The different legislation surrounding web accessibility can be quite confusing. To help you navigate the legal landscape, read these tips on how to protect your site from accessibility lawsuits.

Section 508 and the ADA only apply to companies that operate within the USA. If you are within the EU, you will instead be subject to the EU Web Accessibility Directive. Learn more about this directive in this quick overview.