Assess the specific situation Locate the afflicted drain and extent of backup Look at if a number of drains are affected (suggests major line problem) Search for seen h2o injury or overflow Essential DIY Measures Pour boiling water down drain Use plunger suitable for sink/toilet Test baking soda + vinegar https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/