The other day I was asked the question “To what level does any website legally need to be made accessible?”
“The influence of web accessibility on business and industry is more significant when the demands of a client, or potential client, like the US federal government, must be met.” (WebAim.org)
The law that exists today says that if you are the federal government or supply electronic and information technology goods and services to the federal government, then yes, you must comply with Section 508 of the Rehabilitation Act (Section 508 Standards). This law requires “Federal agencies to make their electronic and information technology (EIT) accessible to people with disabilities.” (section508.gov)