Evaluate your situation Track down the influenced drain and extent of backup Test if a number of drains are affected (suggests principal line problem) Look for noticeable drinking water problems or overflow Essential DIY Actions Pour boiling drinking water down drain Use plunger appropriate for sink/bathroom Consider baking soda + https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/