Is it a legal requirement for dog to wear collar or tag in house?

There is no federal law in the United States that requires dogs to wear collars or tags in the house. However, some local ordinances may require dogs to be collared and/or tagged when they are in public places, such as parks or sidewalks. It is always a good idea to check with your local laws to see if there are any specific requirements for dog collars or tags in your area.