The zone of the root chakra, where the Kundalini resides. This image may point to the relief of undigested leftovers, problems one has worked with.
The suggestion here is to “let go.”
From time immemorial, the toilet has been seen as a dark and scary place—in dreams, all places connected to natural functions are demonized.
It is the place of forbidden sexuality—self-gratification and homosexuality—a place full of danger and frightening activities.
It is a place where ghosts and devils do their bad deeds, and the reason why toilets in the past were always outside.
It is a place of taboos, of secrets and forbidden things, a place where budding sexuality and puberty fantasies run amuck.
This dream image also expresses the finality of nature. On one hand, it addresses everything that is transitory and points out that everything material will pass on and has no value. On the other hand, it addresses the meaning of accomplishment, completion. It is, again, an example of the alchemistic idea that gold can be made out of feces. In one sense, the toilet is the place where products are transformed. Such dream images almost always point to a necessary change: you must let go of something, while, at the same time, you must produce something positive. In Norse fables, King Olaf warns his guests not to go to the toilet alone during the night, because they might end up in a dangerous adventure with the Devil.
The toilet has also been considered the place of ghosts.
According to Jung, it is the place of the highest creativity.... Little Giant Encyclopedia
A dream about spring-cleaning is probably inviting you to make a new beginning, start a new life, by getting rid of old muck and rubbish: negative habits and attitudes, energy-consuming anxiety’, a sadomasochistic guilt-complex, etc.... A Dictionary of Dream Symbols
If kitchen sink, clean up, wash up. You are too broad in considering a problem, are not getting the message, including everything but the kitchen sink.
If sinking into something, you are going down into the muck and mire of own emotional state. Stop and make changes; you are headed in the wrong direction. Release yourself of unnecessary burdens.... The Dream Books Symbols