Assess the specific situation Locate the afflicted drain and extent of backup Look at if many drains are impacted (implies principal line issue) 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/