How to Unblock a Sink Without Harsh Chemicals

That bottle of drain cleaner under the sink looks like a quick fix until it isn’t. 

The wrong formula, or too much of it, can eat straight through older PVC pipes. Many unblockers use caustic soda, also known as lye, which reacts with grease and grime but can just as easily wear down plastic fittings. 

One pressure surge later, and you’ve got a leak under your cabinet instead of a clean drain.

According to the plumbers from Caboolture Plumbing and Hot Water, using chemical products like Draino is a bad idea. If they fail to clear the blockage, you’ll still need a plumber, only now they’re dealing with hazardous acids left in your pipes, which makes the job more complex and expensive.

1. First things first – if you can see it, scoop it out!

What you need: Small wrench or pliers, gloves, zip-it tool, wire hanger, or long tweezers

1. Look under your sink and locate the U-shaped pipe (the P-trap). Behind it, you’ll see a small valve with a thin metal rod coming out that connects to your sink’s stopper.
2. Use your fingers to unscrew the small valve nut where the rod connects. Once it’s loose, slide the metal clip (the little “doohickey”) off the rod.
3. Pull the rod gently out of the pipe. This releases the stopper mechanism inside your sink.
4. Go back to the top of your sink and lift the stopper straight out. You’ll probably notice a bit of gunk attached.
5. Wipe off the stopper and use a zip-it, wire hanger, or long tweezers to remove any remaining hair, soap scum, or buildup from the drain.
6. Reinsert the stopper, slide the rod back into place, and secure the clip and valve nut again. Make sure the stopper moves up and down smoothly when you test it.

Pro tips:

• If you’d rather not deal with stuck stoppers in the future, you can leave it out completely and use a removable strainer instead.

Stop here if: water still pools or rises. Move to Step 2.

2. A quick plunge might be all it takes

What you need: sink plunger (the cup style), wet cloth, bowl or cup.

Steps

1. Remove most standing water, leaving 3–5 cm over the drain so the plunger can seal.
2. Block any overflow holes with a wet cloth for better pressure.
3. Place the plunger over the drain and press down to seal.
4. Plunge with firm, short pumps for 20–30 seconds.
5. Lift the plunger to break the seal and check the flow.

Repeat 2–3 rounds. Between rounds, run hot tap water for a few seconds.

Pro tips

• If it’s a double sink, plug the other drain so pressure stays where you need it. For bathroom basins, remove the pop-up stopper first if possible.

Stop here if: the water does not improve after three rounds. Go to Step 3.

3. If nothing’s working, clean out the pipe underneath

What you need: bucket, old towel, adjustable pliers or channel locks, small brush or bottle brush, rubber gloves.

Steps:

1. Put a towel in the cabinet and set a bucket directly under the P-trap (the U-shaped pipe).
2. Loosen the trap’s slip-nuts by hand.
3. Scrub the inside of the trap and remove any solid clog.
4. Reassemble the trap. Hand-tighten the slip-nuts, then give a gentle tweak with pliers.
5. Run water and check for leaks. Tighten a touch more if you see drips.

Pro tips:

• Chances are, your clog’s hiding right in the P-trap. Give it a rinse and change any cracked washers before reattaching.

Stop here if: the trap was clear and the blockage seems further down the wall pipe. Consider Step 5 tools, then a plumber.

4. Go natural with a quick baking soda and vinegar fix

Remember: slow drains and light grease or soap buildup only. Not for solid blockages.

What you need: baking soda, white vinegar, kettle or pot for hot (not boiling) water, small jug.

Steps:

• Pour about ¼ cup baking soda into the drain. Use a small funnel if needed.
• Slowly add 1 cup white vinegar. It will fizz up.
• Cover the opening loosely with a cup or plug to keep the reaction in the pipe.
• Wait 10–15 minutes. Flush with a full kettle of hot water.

Pro tip: Hot is good but boiling water can be risky for some PVC and seals. This works best as maintenance after Steps 1–3 or as a monthly flush.

Stop here if: the water backs up immediately or the drain is fully blocked. Use Step 5.

Why Plumbers Warn Against Harsh Drain Cleaners

You’ve probably poured a drain cleaner down the sink before. But here’s the thing: those same chemicals that cut through grease can burn your skin, sting your eyes, and send up fumes that irritate your lungs. It only takes a curious child or a pet sniffing too close for things to turn dangerous. 

Before you reach for that bottle again, think about what can happen if even a tiny splash or drop goes where it shouldn’t.

• Getting sodium hydroxide on your skin can cause intense burning and severe pain.
• A splash into the eyes can lead to immediate pain, redness, and even vision loss
• Direct contact can damage tissue within seconds

Why Some Jobs Are Best Left to the Plumbers

There’s a quiet satisfaction in fixing something yourself especially when it’s done safely. No harsh fumes, no panic, just a simple, clean fix that makes your home feel like it’s running smoothly again.

But when the clog sits deeper in the line or keeps coming back, that’s where plumbers step in. They use inspection cameras to see exactly where the blockage is, and specialized tools like drain augers or hydro jets to clear it out completely. More importantly, they understand your home’s plumbing layout, water pressure, and pipe materials, so they can fix the issue without causing damage.