If you dream of seeing a city under water, what kind of omen is that?

Since i was a child, about seven. I have always had the same recurring dream during the late summer early fall, of a city under water. Now, it sound silly but the movie What dreams may come, has the same look of the city I see. Believe me I have told all of my friends about the deja vu that came when I watched that movie. What does a city under water mean?