Blocked Drain? Here's What's Causing It and How to Fix It

Kitchen sink, shower, or outside drain blocked? Try these DIY methods first. If it's a main sewer line, here's how to tell — and what it costs.

Diagnose Your Problem

What Is a Blocked Drain Problem?

A blocked drain happens when water can't flow freely through your pipes — it either drains very slowly or doesn't drain at all. Blockages form when debris, grease, hair, or foreign objects build up inside the pipe until they restrict or completely stop water flow.

In South African homes, the most common culprits are grease build-up in kitchen drains and hair in bathroom drains. Older homes in older homes sometimes have narrower clay or cast-iron pipes that block more easily than modern PVC plumbing.

Most partial blockages can be cleared quickly, but if left untreated they turn into full blockages — and can put backpressure on your pipes, leading to leaks or overflow.

Common Symptoms & Warning Signs

What Causes a Blocked Drain Issue?

Most household blockages happen gradually. Grease and hair combine with soap residue to form a sticky mass that slowly narrows the pipe. In South African homes,'s older suburbs, ageing pipes can also develop rough internal surfaces that catch debris more easily.

Need a qualified plumber? Fonster connects you with vetted plumbers in your area.

How Urgent Is This?

A slow drain is a medium-urgency problem — it won't cause immediate damage, but ignoring it for weeks can lead to a complete blockage, pipe backpressure, and eventually overflow or a leak. If the slow drain is in your kitchen, grease can harden inside the pipe and become much harder (and more expensive) to clear.

If multiple drains are blocked simultaneously, or if wastewater is backing up into other fixtures, treat it as high urgency — this points to a main sewer line blockage that requires a plumber immediately.

How to Tell What's Wrong With Your Blocked Drain Issues

The signs you notice at home can help determine how serious the issue is and how quickly a professional should attend.

What you may notice

  • Single drain emptying slowly
  • No smell or other fixtures affected
  • Occasional gurgling after water drains

This usually indicates:
Localised partial blockage from hair, grease, or soap build-up close to the drain opening

Urgency: Medium

Recommended action:
Try a plunger or drain snake. If not resolved within 1–2 attempts, call a plumber to clear it properly before it worsens.

What you may notice

  • Two or more drains blocked at the same time
  • Water backing up into bath or basin from another fixture
  • Gurgling from toilet when sink drains

This usually indicates:
Blockage in a shared drain line or the main sewer pipe serving multiple fixtures

Urgency: High

Recommended action:
Do not use any drains or flush toilets. Call a plumber today — a main-line blockage requires professional clearing to prevent sewage backup.

What you may notice

  • Wastewater backing up out of a drain or toilet
  • Sewage smell throughout the house
  • Drain overflowing onto floor

This usually indicates:
Complete sewer line blockage or collapse causing sewage to back up into the property

Urgency: Emergency

Recommended action:
Stop using all water in the home immediately. Call an emergency plumber now. Sewage backup is a health hazard and can cause serious structural damage within hours.

DIY vs Professional Repair

You can safely try a plunger or a hand drain snake for simple, single-fixture blockages. Avoid pouring boiling water into PVC pipes as it can soften them. Chemical drain cleaners work on light blockages but damage older pipes and seals with repeated use — use sparingly.

Call a plumber if: plunging doesn't clear the blockage after a few attempts, more than one drain is blocked, or you suspect the blockage is in the main sewer line. A licensed plumber has drain snake machines and CCTV drain cameras to locate and clear blockages without damaging your pipes.

What Professionals Actually Do

A plumber will start by identifying which drain is blocked and how far down the blockage is. For simple blockages they'll use a powered drain snake (electric eel) to break up and remove the obstruction. For stubborn or deep blockages, high-pressure water jetting is used to blast the pipe clean.

If the cause is unclear or the blockage keeps returning, a CCTV drain inspection camera is inserted to visually inspect the pipe and identify root intrusion, collapsed sections, or build-up. The plumber will then advise on the best permanent fix.

Property Damage Risks

An untreated blocked drain can create back-pressure in your plumbing system, which stresses pipe joints and seals. This can cause leaks at the weakest point — often under a vanity cabinet or in a wall cavity — leading to water damage and mould growth that's costly to remediate.

In the worst case, a fully blocked sewer line causes wastewater to back up into your home, which is a serious health hazard and can damage flooring, cabinetry, and subfloor structures. Remediation after a sewage backup can run into tens of thousands of rands.

Frequently Asked Questions

How quickly can you unblock a drain?

We aim for same-day service, often arriving within hours for urgent blocked drain issues.

What causes blocked drains?

Common causes include grease buildup, hair, foreign objects, tree roots, and structural damage to pipes.

Do you use eco-friendly methods?

We prioritize safe and effective methods, including high-pressure jetting, that are environmentally friendly.

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Paarl

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Parow

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