A flood in a dream usually reflects emotions that have outgrown their usual container -- feelings you've been managing that are now simply too much to hold back. Watching the water rise from a distance can mirror a slower buildup, while being swept up in it often names a sense that control has already slipped away.
When a Planet is within five degrees of the cusp of any house, it shall be accounted to have virtue in that house though actually posited behind the cusp in another house. - Cardan Girolamo (1501-1576)