At present, Federal law does not require that each and every public restroom be equipped with a baby changing station. However, many restaurants, hospitality establishments, and other public-facing business types provide them as a way to improve customer service. That means having baby stations is a smart move if you intend to run a business.
Furthermore, if you do decide to utilize these types of accommodations- and we recommend that you do- the Americans With Disabilities Act (ADA) has laid out some specific guidelines for baby changing stations. These regulations are designed to make these items safe to use both for the infant being changed and the parent using them, and to be safe and usable by persons with disabilities.