Blocked drain? What to do, what not to do, and how to prevent it

A blocked drain never picks a good moment. The toilet won't flush on a Sunday night, the kitchen sink fills up with guests on the way, or the gully outside starts bubbling up something you'd rather not smell. This guide covers what to do in the first few minutes, what you can safely try yourself, the drain myths that make things worse, and how to stop it happening again.

What to do when a drain blocks: step by step

1. Stop the water. Don't flush the toilet again "to see if it goes", and ask everyone in the house to hold off on showers, the dishwasher and the washing machine. Every litre you add has to go somewhere, and if the pipe is blocked, that somewhere is usually your floor.
2. Work out what is blocked. One slow basin or one toilet usually means a local blockage in that fitting or its short branch pipe. If several fittings are slow at once, a toilet gurgles when you run the bath, or water rises in the shower when you flush, the blockage is further down in the main sewer line.
3. Check the gully outside. The gully is the open drain with a grid, usually outside the kitchen or bathroom. If it's overflowing or the water is sitting high in it, the problem is in the main line between the house and the street, not in the sink.
4. Try a plunger - properly. Use a cup plunger for sinks and basins and a flange (toilet) plunger for toilets. Block the overflow hole with a wet cloth first, make sure there's enough water to cover the cup, and use ten or so firm, steady pushes and pulls rather than one big shove.
5. Clear the trap on a sink or basin. Put a bucket underneath, unscrew the U-bend or bottle trap by hand, and clean it out. Hair, soap and food scraps collect here and it is the most common basin and sink blockage we see.
6. Take photos and note what happened. When did it start? Has it happened before? Is it one drain or several? This helps a plumber arrive with the right equipment - and you can add photos straight to our booking form.
7. Know when to stop. If a plunger and a trap clean haven't sorted it within fifteen minutes, stop. Pushing harder with a coat hanger or a borrowed snake is how a blockage becomes a cracked toilet pan or a pipe pushed off its joint.

When to call a plumber

Call a plumber if:

• more than one fitting is blocked, or the gully outside is overflowing
• sewage or dirty water is coming up through a shower, bath or floor drain
• the same drain blocks again within weeks or months
• you can smell sewage in the garden or inside the house
• you've already put a chemical drain cleaner down it (tell the plumber - it matters for their safety)
• you're simply not sure. A quick call costs nothing, and we'll tell you honestly whether it's something you can try yourself first.

How we clear blocked drains

Every blocked drain is different, which is why we carry more than one way to clear it. We start with the simplest method that will do the job, and only go further when the drain tells us to.

Drain machines and rods

For most household blockages, a drain machine or rods will break up or pull out the cause - a wad of wipes, a grease plug or a toy - quickly and cleanly.

High-pressure drain jetting

A machine punches a hole through a blockage; high-pressure drain jetting cleans the whole pipe. The jetter sends water at high pressure through a special nozzle that scours grease, scale, silt and fine roots off the pipe walls and flushes them away, bringing the pipe back to its full diameter. It's the right choice for grease-heavy kitchen lines, silted stormwater drains and any line that keeps blocking, because a clean pipe stays clear far longer than one with a hole poked through the middle.

CCTV drain camera inspection

If a drain keeps blocking, something is causing it. A CCTV drain camera inspection sends a waterproof camera down the line so we can see exactly what's going on inside: tree roots coming in at a joint, a cracked or collapsed clay pipe, a sagging (bellied) section that holds water, or an old pipe that was badly joined. You see the footage too, so you know exactly what you're paying to fix - and exactly what you don't need to.

Drain location with our locating equipment

Seeing the fault is only half of it - you also need to know where it is. Our camera head carries a sonde, a small transmitter. On the surface, our locating equipment picks up its signal and pinpoints the camera's exact position and depth underground. That means we can mark the precise spot on your lawn, paving or driveway and dig one hole instead of an exploratory trench. The same equipment is used to trace and map where your drain lines run - useful before building an extension, laying paving, planting trees or buying an older house.

Common drain myths (and the truth)

What not to do with a blocked drain

• Don't keep flushing a blocked toilet. Each flush pushes the water level closer to the rim.
• Don't use chemicals and then plunge. Plunging a drain full of drain cleaner can splash caustic water onto your skin and into your eyes.
• Don't force wire, hangers or hired machines into a toilet or pipe you can't see. Scratched pans, pierced pipes and dislodged joints are common results.
• Don't open a sewer manhole or rodding eye that's full of sewage without gloves, eye protection and a plan for where it will drain.
• Don't dig to find a drain "roughly where it should be". Locate it first - a camera and locator will tell you exactly where and how deep.
• Don't let rainwater run into your gully. A gully should sit slightly above the surrounding ground. Stormwater isn't allowed into the sewer system, and in a Cape Town winter storm it can overload your drains and flood the yard.

How to prevent blocked drains

In the kitchen

• Scrape plates into the bin before rinsing them.
• Pour cooking fat and oil into a jar or tin, let it set, and bin it.
• Use a sink strainer to catch food scraps, and empty it daily.

In the bathroom

• Only toilet paper goes down the toilet. No wipes, sanitary products, cotton buds, dental floss or paper towel.
• Fit hair catchers in showers and baths, and clean basin pop-up plugs every month or two.
• Keep a bin in every bathroom so nobody is tempted to flush things.

Outside

• Keep gully grids in place and clear of leaves and garden refuse.
• Think before planting trees near your sewer line. Roots are the main cause of repeat blockages in older homes - read more in what causes blocked drains in older Cape Town homes.
• Know where your drain lines run. We can trace and mark them for you before you pave, build or plant.

Maintenance

• If a line has blocked more than once, a camera inspection finds the cause instead of clearing the symptom again and again.
• Kitchen and grease-heavy lines benefit from high-pressure jetting every so often to keep them at full bore.
• Buying an older house? A drain camera inspection before transfer can show root damage or broken pipes before they're your problem.

Frequently asked questions

How do I know if my main sewer line is blocked?

If more than one fitting is affected, a toilet gurgles when other water is used, water rises in the shower when you flush, or the gully outside is overflowing, the blockage is in the main line rather than a single fitting. That needs proper drain equipment.

Why does my drain keep blocking?

Repeat blockages usually have a physical cause in the pipe: roots entering at a joint, a cracked or sagging section, a badly laid pipe, or years of grease build-up. A CCTV drain camera inspection shows us which it is, so it can be fixed properly.

Is a blocked drain my responsibility or the City's?

As a rule, the drains on your property, up to where they connect to the municipal sewer, are the owner's responsibility. If the blockage is in the municipal sewer itself - for example, a manhole in the street overflowing - report it to the City of Cape Town. If you're not sure which side it's on, we can check.

What is high-pressure drain jetting?

Jetting uses water at very high pressure, through a special nozzle, to scour grease, silt, scale and fine roots off the inside of a pipe and flush them away. It cleans the full diameter of the pipe rather than just punching a hole through a blockage.

Can you find a drain without digging?

Yes. Our drain camera carries a sonde transmitter, and our locating equipment on the surface picks up its signal to show the exact position and depth of the pipe or fault. We mark the spot so that any digging happens in one place only.