Plumber inspecting a severely blocked drain with visible tree roots, grease, and debris in Sutherland Shire.

Common Causes of Blocked Drains in Sutherland Shire

May 29, 20250

Blocked drains are a common issue for homeowners across Sutherland Shire from beachside homes in Cronulla to older properties in Engadine. While some blockages happen suddenly, most develop gradually due to everyday habits, environmental factors, and ageing infrastructure. Understanding what causes blocked drains is the first step to preventing them. In this guide, SE Plumbing breaks down the most common culprits behind drainage issues and how to avoid them.

1. Tree Root Intrusion

One of the most common causes of blocked sewer and stormwater pipes in the Shire is tree root invasion. Roots are naturally drawn to moisture, and older clay pipes with small cracks or loose joints provide an easy entry point. Once inside, the roots expand and create a dense blockage that restricts water flow.

  • Common in leafy suburbs like Miranda, Gymea, and Sylvania
  • Often occurs in properties with established gardens or large trees
  • May cause recurring blockages, slow toilets, or gurgling sounds

If you suspect tree root damage, our Blocked Drains service includes CCTV inspections to confirm and clear the issue.

2. Grease and Fat Build-Up

Pouring oil, grease, or cooking fat down the kitchen sink might seem harmless, but over time, it creates a thick, sticky coating inside your pipes. This fatty build-up traps food scraps and hardens, eventually leading to a complete blockage.

  • Especially common in kitchen sinks and shared waste lines
  • Leads to slow drainage, bubbling sounds, and bad smells
  • Can affect multiple units in apartment buildings

For severe blockages caused by grease, our Emergency Plumbing team uses high-pressure water jetting to clear pipes safely and effectively.

3. Hair and Soap Scum

Bathroom drains are frequently blocked by a combination of hair, soap residue, and toothpaste. As these materials collect in the pipe, they trap additional debris and slow the water flow.

  • Affects showers, basins, and floor wastes
  • Can cause slow drainage or standing water in the shower
  • Often results in foul odours and drain flies

Prevent blockages by using hair catchers and flushing your drains monthly with hot water and vinegar.

4. Wet Wipes and Sanitary Products

Despite being labelled “flushable,” most wipes do not break down like toilet paper. They catch on pipe joints, build up over time, and cause major blockages. Sanitary products, nappies, and even cotton buds can cause similar problems when flushed.

  • Leads to toilet blockages and sewer overflows
  • Causes problems in both private drains and public sewer systems
  • Can result in backflow into toilets or showers

If this happens, immediate intervention is needed.

5. Foreign Objects

It’s not uncommon for children’s toys, building materials, or accidentally dropped items to enter drains and create a blockage. Even small objects can become lodged in tight bends and cause other materials to build up around them.

  • Common in bathroom and laundry drains
  • Often leads to a sudden, complete blockage
  • May require CCTV inspection to locate the item

We offer Leak Detection and Prevention services to locate foreign objects and identify hidden pipe issues.

6. Garden Debris and Leaves

Outdoor drains and storm water systems are easily clogged by leaves, mulch, dirt, and lawn clippings—especially during storms or after garden maintenance.

  • Can cause outdoor flooding and surface pooling
  • Blocked pits and grates are common in driveways and patios
  • May lead to internal overflow during heavy rain

SE Plumbing clears outdoor drains quickly and safely. Book a storm water drain inspection before the next downpour.

7. Collapsed or Damaged Pipes

Ageing infrastructure is a major contributor to recurring blockages. Many homes in Sutherland Shire still have clay or concrete sewer pipes that crack or collapse over time.

  • Allows soil and debris to enter the line
  • May cause sinkholes or uneven ground in your yard
  • Difficult to detect without a drain camera

Learn more about repairs on our Broken or Damaged Pipes page.

8. Incorrect Pipe Slope or Installation

Drains rely on gravity to move wastewater. If a section of pipe was installed without the correct slope, waste will pool instead of flowing, eventually leading to a blockage.

  • Common in renovated homes or DIY builds
  • Often causes repeated blockages in the same location
  • Requires excavation or relining to correct

Our licensed team can assess and recommend long-term solutions.

9. Scale and Mineral Build-Up

Hard water can lead to mineral deposits inside your pipes. Over time, this scale restricts flow and causes water pressure issues, particularly in hot water and older galvanised systems.

  • Affects taps, showers, and laundry drains
  • Often misdiagnosed as a hair or soap blockage
  • Can be flushed using specialised plumbing tools

Contact SE Plumbing for preventative maintenance and advice on managing hard water issues in your area.

Blocked drains are often caused by a combination of daily habits, environmental factors, and ageing pipework. Whether you’re dealing with tree roots, grease, wipes, or collapsed pipes, early action is key. SE Plumbing offers fast, reliable blocked drain services throughout Sutherland Shire. We use the latest diagnostic tools to identify the cause and resolve the problem properly, the first time.
Call SE Plumbing on 0414 651 351 or book your inspection online today and keep your drains flowing freely.