In 1986, the National Council on Disability had recommended the enactment of an Americans with Disabilities Act (ADA) and drafted the first version of the bill which was introduced in the House and Senate in 1988. The final version of the bill was signed into law on July 26, 1990, by President George H. W. Bush. It was later amended in 2008 and signed by President George W. Bush with changes effective as of January 1, 2009.
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.
I own a medical practice in California with 5 employees. Since I have under 15 employees am I exempt from needing to have my website comply with the ADA? I know that my physical practice is exempt from ADA policies regarding employment (under 15) but I don’t know if that extends to websites. My website is not an important part of my practice and I don’t really want to sink any funds into it if I don’t need to.