Plumbing problems come in all levels of complexity and types, but even if it’s just a broken faucet or a leaky tap in the bathroom, the best thing you can do is call trusted plumbers. In my case it’s https://bens.plumbing/services/sewer-line-repair/shared-side/, but I’m sure there are great specialists in your city too. Trying to fix it yourself really isn’t worth it. Chances are you’ll just have to redo everything anyway.