When it comes to boating safety in the United States, boaters are required to observe Federal Laws, Federal Regulations, Coast Guard Directives and State Boating Laws. It’s no wonder there is some confusion regarding the requirement of mirrors on boats.
The simple answer is that every state requires boaters to have a wide-angle mirror and/or competent observer present when pulling a skier. Almost half the states require both.
A good, wide-angle mirror should allow you to easily see from port to starboard without having to turn around. The person(s) being towed should be in full view at all times.
To see if your state requires a boat mirror when pulling a skier, you can check the National Association of State Boating Law Administrators web site – NASBLA.org.