What’s the difference between a blocked drain and a blocked sewer?

Let’s start with the basics.

A blocked drain

This refers to a blockage in an individual fixture’s pipe, such as the kitchen sink, bathroom basin, shower or laundry. It typically affects a single point in your home and is often caused by a build-up of grease, hair, soap or foreign objects.

Common signs include:

Water draining slowly from one fixture
Gurgling noises when water goes down
Localised smells (often from the kitchen or bathroom)
Water backing up into the fixture

A blocked sewer line

This is a more serious issue. It affects the main wastewater line that collects all your household’s used water and waste and directs it to the council sewer system.

A sewer line blockage is often caused by tree root infiltration, cracked pipes, fat and debris build-up or ground movement, and it usually affects multiple areas of the home.

Signs of a blocked sewer line include:

Multiple fixtures draining slowly or backing up
Toilets that won’t flush or fill to the top before draining slowly
Overflowing outdoor drains or gully traps
Sewage smells inside or outside the house

What causes these blockages?

While blocked drains and sewer lines are different in scale, they often share similar causes:

Tree roots: A major problem in leafy suburbs like Willoughby, Mosman and North Ryde. Roots invade cracked joints and grow inside pipes, eventually causing complete blockages.
Foreign objects: Hair, sanitary items, wipes, food scraps and grease buildup are frequent culprits in household drains.
Old or poorly installed plumbing: Ageing clay pipes, shallow pipework or poorly sloped drains increase blockage risks.
Stormwater ingress: In heavy rain, water can overwhelm the system, especially where illegal stormwater-sewer connections exist.

DIY or professional help?

If you’ve got a slow-draining sink or shower, a plunger or drain snake might offer a temporary fix. However, if the issue is recurring, affects more than one room or involves unpleasant odours or outdoor overflow, it’s time to call a professional.

At STS Plumbing, we use advanced diagnostic tools like CCTV drain cameras, high-pressure water jetters and sonar pipe locators to identify the exact cause and location of the problem.

Our step-by-step process for blocked drains and sewer lines

Here’s how we help North Shore homeowners get their water flowing again; the right way.

1. Identify the issue

We start by asking the right questions. Are multiple fixtures affected? Has there been a history of tree root issues? Is water backing up outside?

From there, we inspect the affected drains and, if needed, insert a CCTV drain camera to visually assess the condition of your pipes.

2. Clear the blockage

Depending on the blockage type and location, we’ll use:

A manual eel or plunger for minor, close-to-fixture clogs
A high-pressure water jetter to remove grease, sediment and roots from longer pipe runs
An electric Eel/drain snake for tougher tree roots or palm tree roots or older clay systems,

Unlike $99 gimmicks, we don’t just poke a hole in the blockage and walk away. We ensure the pipe is cleared from end to end.

3. Assess the damage

Once the line is cleared, we reinvestigate with the camera to check for pipe damage. If we find cracks, collapse or ongoing root infiltration, we’ll walk you through your options — from ongoing maintenance to pipe relining or pipe replacement.

4. Recommend a long-term solution

Sometimes the fix is simple. Other times, damaged pipes need relining or excavation. Whatever the case, we’ll explain your options clearly and provide a fixed quote.

Why you shouldn’t fall for $99 drain cleaning deals

You’ve probably seen ads offering to clear blocked drains for less than $100. Sounds great, right?

Unfortunately, these deals often involve:

Poking a hole in the blockage to temporarily restore flow
Showing you footage of the damage and quoting tens of thousands for urgent repair
Pressuring you into costly excavation work without context

At STS Plumbing, we believe in upfront, honest service. We provide a full clean-out of the line, not a patch job, and explain what’s really going on so you can make an informed decision.

Sewer pipe relining: a smarter solution

If your main sewer line is cracked, sagging or filled with roots, full replacement isn’t your only option.

Pipe relining allows us to insert a new internal lining into your existing pipes without digging up your garden. It’s cost-effective, fast and long-lasting, and ideal for many homes in North Shore suburbs where access is limited. And can save damage to gardens and driveways

We’ll let you know if your property is suitable for relining after a camera inspection.

FAQs: what homeowners want to know

Q: Can I just use chemical drain cleaners from the shop?

A: Not recommended. Harsh chemicals can corrode pipes, harm the environment and offer only a temporary fix. Plus, they don’t work on tree roots or deep blockages.

Q: How quickly can you respond to a sewer emergency?

A: We offer fast callouts across the Lower North Shore. Whether it’s a weekend blockage or weekday backup, we’ll get to you promptly.

Q: Do you charge for diagnosis?

A: Yes, but we’re upfront about all fees. We include CCTV inspection as part of our service when required and always provide honest advice.

Q: Do you service commercial properties or strata blocks?

A: Absolutely. We work with real estate agencies, strata managers and commercial clients across Sydney.

Why choose STS Plumbing?

We’re based in Lane Cove and proud to serve the Lower North Shore. With decades of experience and the latest tools, we get your drainage problems sorted properly, without the scare tactics or hidden costs.