May I ask if there is such a drain in the bathroom, it is still sealed, what is the use, it can be f

Leave a drain on the floor level of the bathroom to prevent water from flowing to other rooms under special circumstances. When decorating, remove the closure and add a floor drain.

This mouth can be opened, the hole diameter is as big as the toilet, used to repair the dredging problem of the sewer, try not to block, the surface can be smeared with a little cement on the surface of the dry sand filling plane, and it can be easily removed when used.

Put a mop pool, wash the mop, and don't block it.

It is best to keep it, and it can be covered with round bricks or fitted with a floor drain.

That's the floor drain, where the water on the floor of the bathroom goes, and it can't be closed.

There are three drains in the bathroom, one is the sink and one is the mouth of the stagnant water, and there is another one for the bath, these are all useful, and the one you took should be left with stagnant water. It is recommended not to seal.