Blocked Drains, this is How to clear a block drain. Blocked drains are one of the most common plumbing problems that people encounter every day through Australia and around the world. Blockages can strike when you least expect, so it pays to be prepared to deal with one. Left untreated blockages can cause water to leak from your drain, potentially damaging your home or business facility. Here's a look at the primary options you have available to you to get rid of blocked drain.