Assess your situation Track down the impacted drain and extent of backup Verify if various drains are impacted (implies major line issue) Try to look for noticeable h2o harm or overflow Essential DIY Techniques Pour boiling water down drain Use plunger appropriate for sink/bathroom Try baking soda + vinegar Resolution https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/