Is it illegal to dig and fill the house warehouse?

It is an illegal building. Although the abandoned pit has not been used for a long time, it is still the natural resource of the country. It is a typical illegal building behavior to fill a big pit to build a house without going through any formalities.

If you really want to develop and utilize it, you can apply to the relevant departments first, and it is not too late to finish all the formalities before building it. The natural resources of the country must be developed and utilized reasonably and legally, and nothing illegal should be done.