Evaluate your situation Find the impacted drain and extent of backup Check if many drains are impacted (implies principal line issue) Hunt for visible drinking water damage or overflow Standard Do it yourself Methods Pour boiling h2o down drain Use plunger appropriate for sink/bathroom Check out baking soda + vinegar https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/