Evaluate the problem Find the affected drain and extent of backup Look at if a number of drains are affected (suggests primary line difficulty) Seek out visible drinking water destruction or overflow Standard Do it yourself Measures Pour boiling h2o down drain Use plunger appropriate for sink/toilet Test baking soda https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/