If you're installing a brand-new bathroom or redesigning an existing one, you should definitely consider the range of ADA-compliant bathroom layouts. The ADA is the Americans with Disabilities Act, and it attempts to ensure that persons with disabilities will have equal access to—and convenience in—public spaces, via a range of codes and recommendations.
If the bathroom you're designing will be in your home, you have no obligation to follow ADA code. However, there are many benefits to doing so, including potential use by aging family members, added resale value, and the fact that you'll be creating a space that can be used by anyone who visits your home, regardless of their range of abilities.
The most prevalent aspect of ADA compliance is measurement and spacing of various bathroom elements. A good example is the shower—ADA compliance requires that roll-in showers (able to be used by someone in a wheelchair) have dimensions of at least 36 inches by 36 inches, and a seat installed along the entire length of the wall opposite the shower valve control. Additionally, the shower curb must not exceed half an inch, and the shower spray mechanism must be equipped with a 60 inch hose that enables fixed showerhead and handheld use. Grab bars and handrails must also be present, and they must meet guidelines for dimensions, strength and spacing.
Tubs, toilets, sinks and urinals all have their own set of ADA guidelines. If you're required to comply with these guidelines for your business, or if you've chosen to in your home, you'll find the full range of compliance guidelines online at via the ADA