Skip to content
Plumbers Adelaide

Drains

How to Unblock a Drain (and When to Call a Plumber)

Most slow drains clear with a plunger, hot water, or a drain snake. This guide shows the steps that work and the warning signs that mean the blockage is past DIY.

6 minute read

To unblock a drain, remove the visible debris, pour 4 litres of hot (not boiling) water down the drain, then work a plunger over the opening for 30 seconds. If water still backs up, a drain snake fed 3 to 4 metres into the pipe clears most remaining blockages. When none of that works, the blockage is deeper in the line and needs a licensed plumber.

Key takeaways

  • A plunger, hot water, and a hand-fed drain snake clear roughly 8 in 10 household blockages.
  • Skip caustic chemical drain cleaners. They damage older Adelaide pipework and rarely shift a solid blockage.
  • Repeat blockages, sewage smell, or more than one fixture backing up at once means the problem is in the main line.
  • A basic blocked drain in Adelaide runs 220 to 480 dollars, so a 30-minute DIY attempt is worth making first.

Work out where the blockage actually is

Before you reach for any tool, find out how far the problem spreads. If one sink drains slowly, the blockage sits in that fixture's trap or branch pipe and is usually an easy fix. If several fixtures back up together, or the toilet gurgles when you run the kitchen tap, the blockage is in a shared drain or the main sewer line, and that is licensed plumbing work.

Lift the gully trap grate outside, normally near an external wall, and check whether it is holding water. An overflowing gully is a strong sign the blockage is downstream of the house and needs a plumber rather than a plunger.

The DIY steps that actually clear a drain

Work through these in order. Each one is low risk and costs almost nothing, and most blockages give way before you reach the snake.

  • Clear the visible debris. For a sink or shower, pull out hair and gunk from the strainer and the top of the trap by hand or with bent wire.
  • Flush with hot water. Pour about 4 litres of hot tap water steadily down the drain to soften grease and soap. Use hot, not boiling, water because boiling water can crack ceramic and loosen old pipe joints.
  • Plunge with a seal. Cover the overflow hole with a wet cloth, fill the basin with enough water to cover the plunger cup, and push and pull firmly for 30 seconds.
  • Clean the P-trap. Put a bucket underneath, unscrew the trap under the sink, clear it out, and refit it. This catches a large share of kitchen and bathroom blockages.
  • Use a hand drain snake. Feed it 3 to 4 metres into the pipe, turning the handle so it grips the blockage, then draw it back out.

Why caustic drain cleaners are a poor choice in Adelaide

Supermarket drain cleaners feel like the quick option, but they are a bad fit for a lot of Adelaide homes. Plenty of properties built before the 1980s still run earthenware or early PVC drainage, and repeated doses of caustic cleaner degrade those joints and the pipe wall over time.

Caustic cleaners also struggle with the blockages people most often face: a solid mass of hair, a wad of wet wipes, or tree root intrusion. The chemical sits on top of the blockage instead of clearing it, and you are then snaking or plunging through a pipe full of caustic liquid. A plunger and a snake are safer and usually more effective.

When to call a licensed plumber

Stop the DIY attempts and call a licensed Adelaide plumber if any of the following is true. These point to a blockage in the main line or a damaged pipe, and clearing them needs a drain machine, a hydro jetter, or a CCTV camera.

  • The same drain blocks again within a few weeks of you clearing it.
  • More than one fixture backs up at the same time, or the toilet bubbles when another fixture drains.
  • You can smell sewage inside the house or around the external gully.
  • Waste water is surfacing in the garden, the lawn, or at the gully trap.
  • The house was built before 1985 and you suspect tree roots, since mature gardens and clay drains are a common Adelaide combination.

What a plumber does that a snake cannot

A licensed plumber starts with a CCTV drain camera to see the exact blockage and its distance down the line. That step alone tells you whether you are dealing with grease, roots, or a collapsed section, which decides the right repair.

For roots and stubborn build-up, hydro jetting cuts the blockage out with high-pressure water and scours the pipe wall clean. If the camera shows cracked or collapsed pipe, pipe relining repairs the line from inside without digging up the yard. Drainage work on the property side of the inspection point is licensed plumbing work under the Plumbers, Gas Fitters and Electricians Act 1995, so it is not a job to attempt yourself.

Questions

Use hot tap water rather than boiling water. Boiling water can crack ceramic fixtures and soften the seals on older Adelaide pipework. Hot water at around 50 to 60 degrees softens grease and soap just as well without the risk.

A single blockage in a residential drain typically costs 220 to 480 dollars. Hydro jetting with a CCTV inspection runs about 650 to 1,400 dollars, and severe blockages involving tree roots or a collapsed pipe can reach 1,800 to 4,500 dollars.

A drain that blocks again within weeks usually has an underlying cause the plunger never reached: tree roots growing through a joint, a partial pipe collapse, or a long-term grease build-up. A CCTV camera inspection finds the cause so it can be fixed once rather than cleared over and over.

Bicarb and vinegar can freshen a slow drain and shift light residue, but the fizzing reaction has very little force. It will not clear a solid blockage of hair, wipes, or roots. Treat it as a maintenance rinse, not a fix for a fully blocked drain.

If only one fixture is slow, a 30-minute DIY attempt with a plunger and a snake is worth it. If multiple fixtures back up, you smell sewage, or waste water is surfacing outside, skip the DIY and get matched with a licensed plumber, because the blockage is in the main line.

Compare 3 free quotes from CBS-licensed Adelaide plumbers

Tell us the job once. We match you with 3 independent local plumbers within 24 hours. No call centres, no obligation, no nasty surprises.

Every plumber CBS-licensed under the SA PGE Act 1995

Get 3 Free Plumbing Quotes