Tools do exist that assist website developers in making their sites more accessible for those with disabilities. Browsers are also key in web accessibility. The challenge is designing a site and software that meets different users’ needs, preferences and situations. Web accessibility also can benefit those without disabilities, specifically those with a temporary disability such as a broken arm, aging, and slow Internet connections. The accessibility testing tool you should use depends on your site’s needs and budget among many other factors.
The ADA itself holds different organizations to more/less stringent standards based on a host of factors, government funding being a major one. Government agencies themselves are usually held to the most severe standards. That said, while ADA has adopted WCAG as the defacto standard, from what I’ve seen it appears they’re going with AA compliance as the most reliable one. That said, we’ve done work with some organizations who’ve chosen to comply with AAA in an effort to be as buttoned up as possible from an accessibility and experiential perspective. We’ve also worked with some who have tighter budgers and aim for level A compliance and have a more “react and repair” mindset when they discover anything in their site that is giving someone hardship from an accessibilirt standpoint.
While legal considerations might be your biggest worry, making your site more accessible is simply good customer service. More than 39 million Americans are blind and another 246 million have "low vision," Another one million are deaf in the U.S. Add to that people with mobility issues that prevent them from using their hands and that's a huge portion of the country's buying power.
Distinguishable: To assist color-blind users and those with other visual impairments, color is never used as the sole means of conveying information or prompting the user. Audio lasting more than 3 seconds can be paused, or the volume can be controlled independently of the system volume. Regular text has a contrast ratio of at least 4.5:1, and large text has a contrast ratio of at least 3:1. In addition, text can be resized up to 200 percent without causing issues with the website.
The U.S. Department of Health and Human Services (HHS) also enforces Title II of the ADA relating to access to programs, services and activities receiving HHS federal financial assistance. This includes ensuring that people who are deaf or hard-of-hearing have access to sign language interpreters and other auxiliary aids in hospitals and clinics when needed for effective communication.

Automated compliance checkers may, however, flag some accessibility barriers that don’t actually exist (false positives). Or they may flag barriers as “potential barriers” or “likely barriers” without stating definitively whether or not they are indeed barriers. That’s not too helpful for the accessibility novice. A person with expertise in digital barriers would be needed to determine whether these are actual barriers or not.

In recent cases, the U.S. Department of Justice has repeatedly sided with plaintiffs arguing that a private company’s website needs to be accessible, despite any other mitigating factors. One thing is for certain, however: The number of federal lawsuits alleging violations of the ADA is currently accelerating at a rapid pace. Between January and August 2017, there were 432 ADA lawsuits filed in federal court—more than the total number of ADA lawsuits in 2015 and 2016 combined.

MAGENTA is a web-based accessibility tool developed by the Human Interface in Information Systems (HIIS) Laboratory within the Human Computer Interaction Group. In addition to the WCAG 1.0 guidelines it evaluates the accessibility of websites according to their conformance to guidelines for the visually impaired and guidelines included in the Stanca Act.

Cynthia Says is a program offered through HiSoftware that helps users identify the web accessibility compliance errors in their site, allowing them to test their individual pages on their site through the Cynthia Says portal and providing feedback in a format that is easy to understand for even the least tech savvy users. The portal is part of a joint education and outreach of Cryptzone, ICDRI, and the Internet Society Disability and Special Needs Chapter, educating users in the concepts behind web site accessibility.

The most recent version was released March 11, 2002. The guidelines covered include WCAG 2.0—W3C Web Content Accessibility Guidelines 2.0, Section 508, and U.S. federal procurement standards. The program generates findings of evaluation results, giving step-by-step evaluation guidance, exhibiting results and information within the page and altering the presentation of web pages. It checks single pages automatically, as well as websites or groups of pages, including those with password protected or restricted pages. Supported formats include CSS, HTML, XHTML, PDF documents, and Images. Licenses are available for commercial and enterprise purposes.