A septic tank holds what a household would rather not see, and tradition reads it as feelings left to settle out of sight. An overflowing one points to something that can no longer stay buried.
Does the traditional reading fit your dream, or did it mean something else to you?
My Cosmic Code has a private dream journal. Write a dream down and the app picks out the symbols in it, shows what dream books say about them and, over time, which words recur across your entries. The journal is stored on your device only.