Evaluate your situation Track down the impacted drain and extent of backup Verify if multiple drains are influenced (indicates most important line situation) Try to find obvious water destruction or overflow Simple Do it yourself Measures Pour boiling h2o down drain Use plunger appropriate for sink/bathroom Check out baking soda https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/