If you dream seeing unrelated people in a hot tub, that could mean something bad is going to happen. When some strangers get together, they are usually connected by a common purpose. They maybe in hot soup, over trouble brewing about something. This type of dream is usually a warning. If you can relate to this in your present life, you might like to think about your actions to save yourself from trouble.
If you dream seeing yourself and your romantic partner in a hot tub, then the dream interpretation is that you desire to develop a closer relationship with your partner.