How to Unclog a Drain: 4 Methods That Actually Work

Water backing up in the sink, tub, or shower is one of the most common plumbing problems in any home. Before you reach for the chemical drain cleaner or call a plumber, try these four methods in order. They go from simplest to toughest, and one of them clears the vast majority of household clogs. I have unclogged thousands of drains. This is exactly what works.

What NOT to Do First

Skip the chemical drain cleaner. The caustic stuff does not dissolve hair, which is the number one cause of bathroom drain clogs. It sits on top of the clog, generates heat, and can warp PVC pipes, damage the finish on fixtures, and burn your skin if it splashes. If the chemicals fail and you call a plumber, you have now created a hazardous situation for whoever works on that drain. Plumbers charge extra when they have to deal with chemical-filled pipes. Start with the mechanical methods below. They work better and they are safer.

Method 1: The Plunger (Done Right)

Most people plunge wrong. For a sink or tub, you need a cup plunger, the simple rubber cup shape, not the flange plunger made for toilets. First, seal the overflow drain with a wet rag. Without that seal, your plunging pressure escapes out the overflow instead of pushing against the clog. Run enough water to cover the plunger cup. Then plunge with short, sharp strokes, not slow lazy pushes. You want to create pressure pulses that break up the clog. Fifteen to twenty vigorous strokes, then lift the plunger to see if the water drains. Repeat two or three times. This clears a surprising number of clogs all by itself.

Method 2: Boiling Water and Dish Soap

This works best on kitchen sinks where the clog is grease buildup. Squeeze a good squirt of dish soap directly into the drain. The soap cuts grease the same way it cuts grease on dishes. Then pour a full kettle of boiling water down the drain in stages, waiting a few seconds between pours. The heat melts the grease and the soap carries it away. Do not use boiling water on PVC pipes if the water has been sitting and cooling in the kettle is fine, but a rolling boil poured directly into PVC over and over can soften the pipe joints. For PVC, use very hot tap water instead of a full boil. For metal pipes, boiling water is fine.

Method 3: The Drain Snake (Hair Clogs)

If plunging did not work on a bathroom drain, the clog is almost certainly hair, and you need a snake. A basic 25-foot hand-crank drain auger costs about $25 at any hardware store and will last you decades. Remove the drain stopper first. Most pop-up stoppers lift out or unscrew. Feed the snake cable into the drain slowly, turning the crank clockwise as you push. When you feel resistance, you have hit the clog. Keep cranking and push gently through it, then pull the cable back out. You will pull out a disgusting wad of hair. That is success. Run hot water for a minute to flush the line clear. For tub and shower drains, a $5 plastic hair snake, the flat barbed kind, works just as well for clogs near the surface and you throw it away after.

Method 4: Remove and Clean the P-Trap

If the snake did not reach it, the clog may be sitting in the P-trap, the curved pipe under the sink. Put a bucket under the trap. The trap has two slip nuts, one on each end. Loosen them by hand or with channel-lock pliers. Water will drain into the bucket, so have towels ready. Pull the trap off and dump out whatever is in it. You will probably find the clog right there. Clean the trap, check the washers, and put it back together. Hand-tighten the nuts, then give them a quarter turn with the pliers. Run the water and check for leaks. This looks intimidating the first time, but it is genuinely a ten-minute job once you have done it.

When the Problem Is Bigger Than One Drain

Pay attention to the pattern. If one sink is slow, it is a local clog and the methods above will handle it. If multiple drains are slow at the same time, especially on the ground floor, or if flushing the toilet makes water come up in the tub, the blockage is in the main sewer line. That is beyond DIY. Main line clogs need a professional auger or hydro jetting, and they can indicate root intrusion or a collapsed pipe. Also, if you have a septic system and drains are slow throughout the house, check the septic tank level before anything else. A full tank backs up every drain in the house.

Preventing the Next Clog

Hair is the enemy in bathrooms. A $3 mesh drain cover catches it before it goes down. In kitchens, never pour grease down the drain. Pour it into an old can, let it solidify, and throw it in the trash. Run hot water for 30 seconds after each use to keep grease moving through the pipes instead of settling. Once a month, fill each sink with hot water and pull the plug to flush the line with volume. These tiny habits prevent most clogs before they start.

When to Call a Plumber

Call a pro if multiple fixtures back up at once, if you smell sewage, if water backs up when you run the washing machine, or if you have tried the snake and the P-trap and the drain is still blocked. Sewer line work involves the main cleanout and sometimes excavation. That is not a YouTube-and-a-prayer situation.