Translation:Excuse me, is the bathroom here?
"Is there a bathroom here?" in Chinese is "有洗手间这里吗?" or using the alternative way of asking "有没有洗手间这里?"
"Is there a bathroom here" implies you don't know if there is one. "Is the bathroom here" implies you know there is a bathroom somewhere around but you want to verify its location.
Although I don't rest in restrooms, I don't bathe in them either. In France one gets to the point and asks where the f ing toilet is located.
From what I've read in this forum and other webs, it seems like a regional/dialect difference, but mean the same.