A blocked drain is one of those household problems that goes from minor irritation to expensive emergency very quickly. Before you call a plumber, there are several things you can try yourself. This guide covers the most effective ways to unblock a drain at home — what to try first, what to avoid, and when to stop and call in a professional.
If you live in Cape Town, drains tend to block for predictable reasons: hair and soap build-up in basin and shower waste pipes, fat and food scraps in kitchen sinks, tree roots in older clay outside drains, and sand or grit washed in during winter rains. The fix depends on the cause.
1. Start with boiling water
For a slow-running kitchen sink, the cheapest first step is boiling water. Pour a full kettle slowly down the drain in two or three stages, pausing for 30 seconds between each pour. Hot water softens fat, grease and soap residue and pushes it through the trap. This works well for partial blockages but won’t shift solid debris. Avoid boiling water on plastic-traps and PVC waste pipes that show signs of cracking — very hot water can deform older joints.
2. Try bicarbonate of soda and vinegar
If hot water alone doesn’t clear the blockage, follow it with a chemistry-based approach. Pour half a cup of bicarbonate of soda directly down the drain, then half a cup of white vinegar. The mixture fizzes as it reacts and helps break down organic matter, soap scum and minor grease. Cover the drain with a plug or damp cloth so the reaction works downwards rather than escaping back into the basin. Leave it for 15 to 20 minutes, then flush with another kettle of boiling water.
This is a much safer alternative to caustic shop-bought drain cleaners, which we generally don’t recommend — see our guide on the dos and don’ts of using drain cleaners for the full picture.
3. Use a plunger correctly
A plunger is the most underrated tool in the house, but only if you use it properly. For sinks and basins:
- Block the overflow opening with a wet cloth — otherwise the suction escapes and nothing happens.
- Run enough water into the basin to cover the rubber cup of the plunger.
- Position the plunger directly over the drain hole, then push down and pull up sharply 10 to 15 times in a row.
- Lift the plunger on the last stroke and check whether the water drains.
Use a sink plunger (the small flat-cup type) for basins and a flange plunger (the larger one with a rubber lip) for toilets. Don’t mix them up — the seal won’t work properly.
4. Clear the U-bend trap manually
If plunging doesn’t work, the blockage is probably sitting in the U-bend (the curved section of pipe directly under the basin or sink). Place a bucket underneath, then unscrew the two slip-nuts holding the U-bend in place. Tip the contents into the bucket and clear out anything trapped — usually hair, food, or congealed fat. Rinse the trap with hot water before reattaching it. Hand-tight is enough; over-tightening cracks the threads.
For shower drains, lift the grate and use a wire hook or a flexible drain snake to pull out the hair clog that has almost certainly built up just below the strainer.
5. Check the gully and outside drains
Outside drains in South African homes are usually open gullies — the small grated drain in your courtyard or against the kitchen wall where the kitchen and laundry waste pipes discharge. These block constantly because everything that goes down the inside drains ends up here, and they catch leaves and garden debris on top.
Lift the grate, scoop out any solid debris, and run a hose into the drain at full pressure for 30 seconds. If water backs up, the blockage is further down the line and a domestic hose won’t shift it.
6. Avoid chemical drain cleaners where you can
Caustic soda and the strong supermarket products containing it will sometimes shift a blockage, but they damage older pipework, corrode metal traps, and burn skin and eyes if they splash. They’re also useless against tree roots, broken pipes, or solid blockages — the most common causes of a fully blocked outside drain. If the bicarbonate-and-vinegar method hasn’t worked, jumping to caustics rarely helps. Read our overview of drain-cleaning chemicals for what to use and what to avoid.
7. Know when to call a professional
The DIY methods above clear most household blockages, but there are a few situations where you should stop and call us:
- Multiple drains in the house are blocked at the same time — that points to a main sewer line problem, not a single appliance.
- Sewage is backing up into showers, baths or toilets.
- You can hear gurgling from drains in other parts of the house when one fixture is in use.
- The blockage has been cleared and reappeared within a few days — usually a sign of tree roots or a broken pipe.
- Outside gullies are flooding even after you’ve cleared the obvious debris.
For these, professional high-pressure drain cleaning or drain jetting is the right tool. We use water at up to 4,000 psi to clear roots, hardened grease and debris that a plunger or chemical cleaner won’t touch. CCTV inspection — included in most of our callouts — locates the exact blockage and tells you whether the pipe itself is damaged.
Preventing the next blockage
Most domestic drain blockages are preventable. The basics:
- Never pour fat, oil, or cooking grease down the kitchen sink — wipe pans with paper towel into the bin instead.
- Fit hair-catcher strainers in basin and shower drains. They cost under R50 and prevent the most common cause of bathroom blockages.
- Don’t flush wet wipes, even ones marked “flushable” — they don’t break down and they cause an enormous proportion of municipal sewer blockages, as the City of Cape Town regularly reminds residents.
- Run a kettle of hot water through the kitchen drain once a week to keep grease moving.
- Trim back any trees with roots near outside sewer lines — this is the single biggest cause of repeat blockages we see.
If you’ve worked through this guide and the drain is still blocked, get in touch. We cover the entire Cape Town metro for both domestic drain clearing and emergency callouts, and we’ll diagnose the cause before quoting on the work.
