When a drain blocks, the right blocked drain solution depends on what is causing the blockage and where it sits in the pipe. A plunger, a bottle of drain cleaner and a set of drain rods can all restore flow in the right circumstances, but each one leaves part of the problem in the pipe. High pressure drain cleaning (water jetting) is the only common method that cleans the full bore of the pipe and flushes the debris out of the system. This guide compares the options honestly, explains why jetting is usually the most thorough fix, and covers the cases where it is not the answer.
Start by working out what kind of blockage you have
Before choosing a method, it helps to know roughly what you are dealing with:
- One fixture is slow (a single basin, shower or sink): the blockage is usually close to that fixture, often hair, soap or grease in the trap or the first metre of pipe.
- Several fixtures are slow, or the outside gully is overflowing: the blockage is further down the main drain line, where grease, wet wipes, silt or tree roots are more likely.
- Blockages keep coming back in the same place: there is usually a build-up on the pipe walls, root intrusion or a damaged section of pipe that catches debris.
Our guide to blocked drains: causes, effects and solutions goes into the common causes in more detail.
Blocked drain solutions compared
| Method | Works on | Where it falls short |
|---|---|---|
| Plunger | Soft blockages in a basin, sink or toilet trap | Cannot reach blockages further down the line |
| Hot water and washing-up liquid | A light film of grease in a kitchen waste pipe | No effect on solid blockages, roots or silt |
| Chemical drain cleaners | Hair and soap scum close to the fixture | Hazardous to handle, can damage older pipes, sit uselessly in a fully blocked drain |
| Drain rods or a drain snake | Punching through a blockage to restore flow quickly | Leave grease, scale and root mass on the pipe walls, so blockages tend to return |
| High pressure jetting | Grease, scale, silt, sand, wet wipes and fine roots along the full length of the pipe | Needs professional equipment; not a fix for collapsed or badly broken pipes |
Chemical cleaners deserve a particular warning. Caustic and acid products can burn skin and eyes, give off fumes, and damage older metal and fibre pipes. If a drain is completely blocked they simply sit in the standing water, which makes the job more dangerous for whoever clears it next. See what chemicals are used to unblock drains and the dos and don’ts of using drain cleaners before reaching for a bottle.
Why high pressure jetting is the most thorough blocked drain solution
It cleans the whole pipe, not just a hole through the blockage
Drain rods push through a blockage and open a channel. Water starts flowing again, but the grease and debris coating the pipe walls stays put and starts catching new material straight away. A jetting nozzle scours the full circumference of the pipe as it travels, so the pipe is returned close to its original diameter.
It flushes the debris out of the system
Loosened material is washed down the line to the next manhole or out to the municipal sewer connection, rather than being left in the pipe to settle again.
It deals with grease and scale
Kitchen waste pipes and the drains below restaurants build up hardened fat, oil and grease over time. Rodding barely touches this layer. High pressure water cuts it away, which is why commercial kitchens use scheduled jetting alongside grease trap cleaning.
It can cut through fine root intrusion
Specialised jetting nozzles clear the fine roots that grow in through pipe joints. Heavy, woody root masses may need mechanical cutting or root extraction, and roots will grow back through the same defect unless it is repaired. Our article on how tree roots affect your pipes explains why.
It uses only water
There are no chemicals involved, which is safer for the people working on the drain, for your pipes and for the environment downstream.
How high pressure drain cleaning works
A jetting unit pumps water at high pressure through a flexible hose fed into the drain from a gully or access point. The nozzle on the end of the hose has a forward jet that breaks up the blockage and several rear-facing jets that pull the hose along the pipe and scour the walls as it goes. The operator matches the pressure and nozzle to the pipe size, material and type of blockage. Our pages on drain jetting and our high pressure drain cleaning service explain the equipment and process in more detail.
A CCTV camera inspection before or after jetting shows exactly what caused the blockage and whether the pipe is damaged. See what is a CCTV drain survey for how that works.
When jetting is not the answer
- Collapsed or badly broken pipes. Jetting can clear debris from a damaged section, but the water escapes through the break and the blockage will return. The pipe needs repair or drain relining.
- Fragile older pipes. Jetting is generally safe on older pipes when the pressure is set correctly, but pitch fibre and badly cracked clay need a lighter approach. See is pressure drain cleaning safe for older pipes?
- A full septic tank. If you are on a septic system and every drain in the house is slow, the problem may be the tank rather than the pipes. See our guide to septic tank emptying.
- A blockage in the municipal sewer. In Cape Town, the City maintains the public sewer mains and property owners are responsible for the drains on their own property. If neighbours are affected too, the blockage may be in the municipal line. The City’s residential water and sanitation services page explains how to report it.
What you can safely try yourself
- Use a plunger on a single slow basin, sink or shower.
- Lift the grate on an outside gully and remove leaves, sand or debris by hand, wearing gloves.
- Stop using the affected fixtures so you do not add to the backlog.
Avoid pouring chemicals into a fully blocked drain and avoid hiring a rod set for a main line you cannot see. Our article on the dangers of DIY drain cleaning explains the risks.
Keeping drains clear after jetting
- Scrape fat and food waste into the bin, not the sink.
- Never flush wet wipes, sanitary products or cotton buds, even those labelled “flushable”.
- Keep gully grates in place and clear of leaves.
- For restaurants and properties with recurring blockages, schedule jetting before blockages happen rather than after.
If you have a blocked drain in Cape Town, our teams clear domestic and commercial drains with high pressure jetting. Contact us about drain clearing services in Cape Town. For general background on the different methods, the Wikipedia entry on drain cleaners is a useful reference.
