Evaluate the problem Find the affected drain and extent of backup Look at if a number of drains are affected (signifies main line situation) Search for seen h2o injury or overflow Essential DIY Techniques Pour boiling h2o down drain Use plunger appropriate for sink/bathroom Check out baking soda + vinegar https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/