A blocked drain, in the simplest terms, is an obstruction to the free passage of water. However, the end result is always the same, water that cannot flow freely down the drain. Anything from tree roots to accumulated garbage might have triggered the issue. A Drain Blocked Sydney may occasionally be unclogged by plunging it with a plunger or by using good old-fashioned elbow grease. However, there are situations when you need the help of a professional plumber immediately.