Evaluate the specific situation Locate the afflicted drain and extent of backup Test if several drains are affected (suggests primary line challenge) Seek out visible drinking water damage or overflow Standard Do it yourself Methods Pour boiling h2o 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/