Assess the specific situation Find the affected drain and extent of backup Verify if several drains are affected (implies most important line challenge) Hunt for noticeable h2o problems or overflow Simple Do it yourself Methods Pour boiling water down drain Use plunger appropriate for sink/rest room Try out baking soda https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/