Evaluate your situation Locate the impacted drain and extent of backup Check if a number of drains are impacted (implies key line situation) Seek out visible water hurt or overflow Simple Do-it-yourself Measures Pour boiling h2o down drain Use plunger suitable for sink/rest room Test baking soda + vinegar Option https://www.kawatan.net/why-you-should-never-use-baking-soda-and-vinegar-to-unclog-a-drain/