Where is the public restroom in Madrid? Look at the map.

Просмотреть увеличенную карту

At least in Madrid there are not many public restrooms. I remember they installed some many years ago, but I don't know if they continue working. Anyway, they were very few.. There are, of course, restrooms at the stations, airports, etc. Not in the Subway, and yes in the medium-long distance trains.

is right that there are limited restrooms outside of restaurants, bars, etc. You most likely will NOT find any restroom inside of the Metro stations but can do so on trains with longer distances to travel. I believe it is Spanish law that all restaurants/bars are required to allow you to use the restroom and ask for a glass of water (free) without paying for it. HOWEVER, it's not something people look favorably upon and don't expect a warm greeting when you ask to do so. Perhaps just order a quick tapa/coffee/etc., and pop into the loo to take care of business and be off. It's not that uncommon to do so.

Yes, that's what we, most Spaniards, do. Ask for a coffee in a bar and use their restrooms. Of course you can use it even if you don't take anything but it is true it is not "polite" and they don't like it. Mc Donald's, Burger King and some other fast food restaurants requiere a password to enter restrooms and you can only get if you buy something.

I have frequently used the McDonald's off Puerta del Sol (kind of opposite La Mallorquina on Calle Mayor) never using a password. In fact, that was the place I was going to recommend. I guess I feel I keep Micky D's in business in both sides of the Pond so I have no guilt using their facilities. Oh, sure, I always buy something...but never a password.