Assess the problem Find the affected drain and extent of backup Verify if various drains are influenced (implies major line issue) Hunt for visible drinking water damage or overflow Standard Do it yourself Actions Pour boiling drinking water down drain Use plunger appropriate for sink/bathroom Try baking soda + vinegar https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/