Home Remedies for a Blocked Drain: What Actually Works
24 May 2026 · Plumbers On Duty
Quick answer
Three home remedies work reliably:
- Boiling water + dish soap — for grease and soap blockages
- Plunger with the overflow covered — for slow basins and toilets
- Removing and cleaning the trap under the basin — for blockages right at the fitting
Three popular ones don't really work:
- Baking soda + vinegar (too weak)
- Cola down the drain (you're literally pouring sugar in)
- Caustic crystals on standing water (sits on top, damages pipes)
What actually works
Boiling water + dish soap
Works because grease is the main binder in most household blockages. Hot water + degreaser dissolves it.
- Boil 2L of water
- Add 2 tablespoons of regular dish soap (Sunlight, Handy Andy, Morning Fresh)
- Pour SLOWLY over 1–2 minutes — fast pouring just bounces back out
- Wait 5 minutes
- Run the hot tap
Repeat once if it's partly cleared. Skip if the basin is full of standing water that hasn't drained — boiling water + PVC + standing cold water can crack the trap.
Plunger (correctly used)
The mistake: people pump frantically and air escapes through the overflow.
The fix: cover the overflow with a wet cloth or your palm, then plunge with slow, firm strokes of about 1 second each. 15–20 strokes should do it.
For a toilet, use a flange plunger (the one with a rubber sleeve that fits into the toilet outlet), not a flat cup plunger.
Cleaning the trap
The U-bend under the basin is where 70% of blockages actually sit. It's literally designed to catch debris before it gets into the main drain.
- Bucket underneath
- Unscrew the two big plastic nuts (hand-tight, or use channel-lock pliers very gently)
- Lower the trap into the bucket
- Clean it out (toothbrush, hot soapy water)
- Check the seals are still soft — replace if hardened (R30 from a plumbing merchant)
- Reassemble, finger-tight is enough
Wet-dry vacuum (if you have one)
Set to liquids. Seal it over the drain with a wet towel as a gasket. Run for 30 seconds. Often pulls the blockage right out into the vacuum.
What doesn't work (despite what the internet says)
Baking soda + vinegar
The chemistry: bicarbonate + acetic acid → salt water + CO2. Looks impressive (fizzing) but the reaction is too weak to break up hair and grease. Don't waste your time.
Cola
Yes, it's mildly acidic (~pH 2.5), but you're also pouring a sugar solution into your drain. Net result: slightly clean drain, very happy drain bacteria, blockage returns faster.
Caustic crystals / "Drano" on standing water
Caustic soda needs to reach the blockage to work. If the basin is full of water, the crystals sink, sit at the bottom of the trap, eat through your PVC pipe over time, and never reach the actual clog. Skin contact also causes serious burns.
If you must use caustic, it's only safe on a slow drain (not a fully blocked one), used once (not repeatedly), with rubber gloves and eye protection.
When home remedies have failed — what next
- Drain snake (R150 hand snake from Builders) — reaches 3–5m
- Plumber call-out: R600–R1,400 for a single fixture
- Main drain rodding: R1,200–R2,500
- Drain jetting (chronic blockage): R2,500–R4,500
Prevent it happening again
- Hair catcher in every shower drain (R30, replace monthly)
- Never pour fats down the kitchen sink — wipe pans into the bin first
- No wet wipes, ever, even "flushable" ones
- Strainer in every sink
- Monthly hot-water + soap flush as maintenance