Most likely, you have water seeping through the seals and so on. I advise you to check the insides of your gaskets and upholstery From the description, I think this is exactly the case 1-1. 5 inches in 3 days this sounds really much, so the problem is not insignificant and it needs to be addressed. I once had a similar problem but related to the sink in the kitchen. I knew a lot about this case, but I did not think that I could handle it myself, however, I did not have the opportunity to call a plumber because of the coronavirus and the pandemic. My friend suggested that I read a couple of articles on https://www.howtobecomeaplumber.org/ and it is possible to find similar cases to figure it out for myself, which I did. I was surprised myself that I could do it, really lol
