Assess the problem Identify the impacted drain and extent of backup Test if many drains are impacted (suggests most important line problem) Try to find obvious water problems or overflow Primary Do it yourself Ways Pour boiling h2o down drain Use plunger appropriate for sink/toilet Try baking soda + vinegar https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/