What Causes Blocked Drains? Prevention Tips for Melbourne Homes

Blocked drains are one of the most common plumbing problems in Melbourne homes — and many are entirely preventable. Understanding what causes blockages helps you avoid expensive call-outs and keep your drainage system running smoothly all year.

The Most Common Causes of Blocked Drains in Melbourne

Hair and Soap Scum (Bathrooms)

This is by far the most common cause of blocked bathroom drains. Hair combines with soap residue to form clumps that gradually build up inside the pipe. A simple drain strainer prevents most of this debris from entering the drain in the first place.

Grease and Food Waste (Kitchen Drains)

Cooking oil and grease might pour down the drain in liquid form, but they solidify on the inside of pipes as they cool. Over time, grease buildup narrows the pipe and traps food particles. Never pour cooking oil or fat down the sink — let it solidify and dispose of it in the bin instead.

Tree Root Infiltration

In older Melbourne suburbs with established trees, tree root infiltration into clay or concrete sewer pipes is a major cause of recurring blockages. Roots are attracted to moisture and nutrients inside the pipe and can crack and infiltrate through even the smallest joint gaps. Once roots are inside, they grow and catch debris, eventually causing a complete blockage.

Foreign Objects in Toilets

Wet wipes (including those labelled “flushable”), cotton pads, sanitary products, and paper towels cause serious blockages. Only human waste and toilet paper should go in the toilet.

Stormwater Debris

Leaves, dirt, and garden debris accumulate in outdoor drains, particularly during Melbourne’s autumn leaf fall and after heavy rain. Regular clearing of visible debris from drain grates prevents stormwater drain blockages.

Pipe Scale Buildup

In Melbourne’s inner suburbs with older galvanised steel pipes, mineral scale builds up on the inside of pipes over decades, gradually narrowing the diameter and restricting flow.

Prevention Tips

• Install strainers or hair catchers in all shower and bath drains
• Never pour cooking oil, grease, or fat down the drain
• Only flush toilet paper — bin everything else
• Regularly clear leaf litter from outdoor drain grates
• Pour boiling water down kitchen drains weekly to keep grease moving
• If you have trees near your sewer line, have it inspected every 2–3 years with a CCTV camera

When to Call a Plumber

If your drain is slow despite attempts to clear it, or if it’s blocked multiple times in a short period, call a licensed plumber. Recurring blockages usually indicate a structural issue — tree roots, pipe damage, or an offset joint — that needs proper diagnosis with a CCTV camera rather than repeated jetting.