Here is a response I drew up for a client who was concerned about ADA Compliance for their website. I'm sharing it here in case it's of use to anyone else.
Thanks for your e-mail. We're delighted to help your site be ADA compliant. In answer to your question, I would say about 5% of our clients have raised concerns about ADA compliance.
Somewhat frustratingly, the ADA compliance regulations are both very detailed and very vague. It sounds so simple when they say:
"Businesses and state and local governments have flexibility in how they comply with the ADA’s general requirements of nondiscrimination and effective communication. But they must comply with the ADA’s requirements."(Per this)
However, this is greatly complicated by the subsequent sentence.
"The Department of Justice does not have a regulation setting out detailed standards."
Basically, the DOJ wants your site to be compliant but is not willing to explain what being compliant is. That's actually pretty understandable - screen reader, browser, and website technology are in a constant state of evolution. Still, it puts everyone in an awkward position.
The DOJ letter does give some examples of what would be compliant, such as adhering to WCAG standards. WCAG has 3 levels of compliance - A, AA, and AAA. They also have those standards in 3 editions: original, version 2, and a version 3 that is in a draft state, meaning not yet fully ratified. It's not evident which version and level DOJ considers to be adequate.
Here is the guideline for edition 2. As you can see, there are around 50 different things to test to see if the site is in compliance. Simply going through each test to understand it and see if the site complies would be an onerous task.
Another concern is, even if the site were to be checked over and pronounced accessible by some party with the time and knowledge to do so (us, or your IT department, for example), websites, by their nature, change. The content changes to accommodate your needs and the underlying code changes to stay compliant with security and the technological environment. Additionally, the definition of compliance, itself, is in flux. Thus, your site might be compliant on Monday but not on Tuesday.
One solution is to apply an ADA compliance enabling plugin like Acessibe. At $500/year, it's not the cheapest solution. I've also been told by one of our clients that the solution applied by the plugin technology is not truly ADA compliant, although given the vagueness of the definition of compliance, I think that's probably hard to determine. Another concern I have is, those with difficulty browsing websites already use screen readers to assist themselves. I don't know what a website plugin could be doing that a screen reader software would not. With that said, I expect a plugin like accessibe would at least marginally improve your degree of compliance while also demonstrating you have taken steps to accommodate ADA requirements. Having an ADA compliance plugin intact also helps ensure ongoing compliance, even as the definition of compliance changes and your website changes.