antiguos lavaderos

Not sure I got the name right... but a current thing that seems to be all the rage for nominating in pueblos and small towns in Spain are antiguos lavaderos. (I keep categorizing under laundromat I think but they aren't. ) They are basically old / historic places where people washed their clothes.
A lot of them are historic landmarks, but most are unsigned and not. In the past, they played important social roles in their communities where women went to work.
I've been 3*ing most of them because they have historic value and I can locate them on a map via Google Street View.
Any guidance on these as a rule of thumb and what they should be classified as would be appreciated.
Comments
If it's a historic structure that is clearly identifiable, you should feel free to rate it well. Doesn't need a historic marker or sign. Just being old does not make something historic, but from what you've described these do sound like they could be places of historical interest, so I think you should just use your best judgment. Is this a place that someone might visit to learn about the culture? If you think that the answer is "yes," then you can rate accordingly.
As far as classifying them, I would be inclined to choose either "Historic Building" or "Historic Structure" (though I kind of like your creative use of "Laundromat"). Keep in mind that the "What Is It?" list is not a list of what's eligible, so not being able to find a good classification isn't a reason to reject a nomination.
I feel like they are so dependent on descriptions but people don't actually write useful ones. It means a lot of guess work. :(