Hey. I am remodeling my bathroom located in the basement. It sits on a concrete floor. I pulled out the vanity and saw there was a plastic cap covering a hole underneath it. There was zero access to the hole with the vanity over it because the vanity sat on the floor. I would like to put in a new vanity that is raised, along with tile floor. I am curious as to what this hole is used for, if I can fill it or tile over it, or what my design options are. Currently the plastic cap is cemented shut so I cannot open it without more work. But is that even necessary?