Is it a law to have a bathroom in your restaurant?

That's the question, is there any rules, ordinances or laws about bathrooms/toilets in restaurants or other establishments?
 
I live in a modern city in China. For the past several years, Subway has come, and there are about 6 to 7 stores around the city, owned by different owners. Some do have toilets, while others do not. I learned this after ordering a sandwich and searching their premesis looking for a toilet, only to be told by the owner that there was none. "Sorry, no toilet." was simply the response.
 
I really took offense at that, and decided not to do anymore business there. That's just cheap. A unisex toilet and sink is all that would be needed. i think the concern is that there will be a lot of people using the toilet without buying something, but I think that by letting people have that convenience, they might stop and get some food. Maybe not.
 
In the USA, are bathrooms mandatory even for small places?

It really depends on where you are. To my knowledge, there's no nationwide standard. As a general rule of thumb, in most but not all places, if you offer indoor seating for people to sit and eat, you generally have to have restrooms available. But that is not, to my knowledge, required everywhere. And rarely is a place without seating required to have a restroom for the public. Generally, most places are required to have restrooms for employees, but public accommodations vary widely with where you are located and what type of business you are.

That law varys by individual states.  Many even require you to have a wheelchair accesible bathroom.  Some places are "grandfathered" by being historical places, but all new places must have them.  This includes, in some states, convenience stores that have any sort of indoor sitting.

Ask your Heath dept rep. Best advice on this question