How to Unclog a Drain: What to Try First, Second, Third

Work in order: pull out what you can reach, plunge with the right plunger, then use a zip tool or snake, and only then open the pipe under the sink. Most clogs in a sink, tub or shower are hair, soap and gunk within a foot or two of the drain, and a plunger plus a cheap zip tool usually clears them. Chemicals come last, if at all.

Quick version

• First, check whether one drain is clogged or several. Several means call a plumber.
• Pull the stopper or cover and remove what you can see. Pull up, don’t push down.
• Use a flat cup plunger on sinks and tubs, a flange plunger on toilets, and block the overflow hole.
• Next: zip tool for hair, hand snake for deeper clogs, closet auger for toilets.
• Skip boiling water on plastic pipes and toilets, and treat chemical cleaners as a last resort.

Before you start: one drain or several?

Run water in the other sinks, flush a toilet, and run the tub. If only one fixture is slow, the clog is local, between that drain and the wall. That’s a DIY job.

If two or more drains back up together, especially on different floors, or water rises in the tub when you flush, the blockage is probably in the main line. A plunger won’t reach it. Call a plumber.

How to unclog a drain, in order of escalation

1. Clear the opening. Lift out the sink’s pop-up stopper (some twist a quarter turn first), lift the kitchen strainer, or unscrew the shower drain cover. Pull out the hair clump with your fingers, needle-nose pliers or a bent wire. Pull up and out; pushing just packs the clog tighter. Run water to test.
2. Try very hot tap water, not boiling. For a slow bathroom drain, a few pots of hot water can soften soap scum. Boiling water can warp PVC pipe and plastic fittings, and it can crack a toilet bowl. If you don’t know what your pipes are made of, stick to hot tap water.
3. Plunge with the right plunger. Use a flat cup plunger on sinks, tubs and showers and a flange (or beehive) plunger on toilets. Leave a few inches of water in the basin so the plunger pushes water, not air. Stuff a wet rag into the overflow hole on a sink or cover the tub’s overflow plate, and plug the second side of a double kitchen sink. Pump hard for 20 to 30 seconds, then pull the plunger off sharply. Repeat a few times.
4. Use a zip tool for hair. Push the barbed strip down the bathroom sink or tub drain as far as it goes, then pull it out slowly. Expect something gross.
5. Run a hand snake. Feed the cable into the drain, turning the handle clockwise. When you hit resistance, keep turning to break up or hook the clog, then pull back slowly and flush with hot water. Never put a regular snake in a toilet; use a closet auger, which has a sleeve that protects the porcelain.
6. Take apart the P-trap (sinks only). If the sink is full, scoop out as much water as you can. Put a bucket underneath, loosen the slip nuts slowly so the trap drains, then remove it and clean it out. While it’s off, look down the pipe toward the wall. Reassemble hand-tight and run water to check for drips.
7. Call a plumber if the snake can’t get through, the clog comes back within weeks, or you’re dealing with an older house where pipes may be fragile.

Chemical cleaners: enzyme vs. caustic

Enzyme cleaners use bacteria and enzymes to eat organic gunk. They’re slow and gentle on pipes, so they’re better for monthly maintenance than for a full clog.

Caustic and acid cleaners (sodium or potassium hydroxide, sulfuric or hydrochloric acid) work faster and carry real risk. If you use one:

• Wear goggles and rubber gloves, and open a window or run the fan.
• Pour slowly and close to the drain. Too much product in a fully blocked drain can splash back.
• Never mix two products, and never pour one right after another.
• Don’t plunge or snake a drain with chemical cleaner sitting in it. If you already poured some and it didn’t work, tell whoever comes to fix it.
• If someone swallows it, gets it on their skin or breathes the fumes, call Poison Control at 1-800-222-1222.

Fixture-by-fixture chooser

What the pros say

• Roger Wakefield, a Texas master plumber, says to scoop standing water out of a clogged kitchen sink before you open anything, then crack the slip nut over a bucket and let it drain slowly so you don’t soak the cabinet and buckle the wood; he also notes the dishwasher usually drains through the disposal, so a clog past that point can back up both. In a side-by-side test of drain cleaners, his team found chemicals hit or miss on grease-heavy clogs and pointed to a mechanical snake or a plumber as the safer path.
• Richard Trethewey, the plumbing and heating expert at This Old House, seats the plunger in a toilet, pushes gently to seal, then pulls back to draw the clog up and break it apart, since shoving can compress it, and uses a closet auger on toilets because a bare wire scratches the china. On a bathroom sink, he blocks the overflow so the force goes down the drain instead of back at you.
• Joseph Wood, owner of Boston Standard Plumbing & Heating, tells This Old House readers to fill the sink with water, stuff a wet rag in the overflow, and plunge hard. If that fails, he unscrews the nut at the back of the drain pipe, pulls out the pivot rod and lifts the stopper, because hair and soap ball up at its base.
• Tammy Zhao, PharmD, a pharmacist and poison information specialist writing for Poison Control, explains that non-enzyme drain cleaners contain strong acids or alkalis that can burn skin and cause serious injury if swallowed. She advises goggles, rubber gloves and careful pouring, and notes that baking soda and vinegar rarely build enough pressure to clear a drain.

Gear that helps

We researched these tools and cross-checked them against what the pros above use and link to; we did not test every one ourselves.

Do this this week

• Find your plunger and confirm you have the right type for each fixture. Buy a cup plunger if you only own a toilet one (it belongs on every first apartment checklist).
• Pull and clean the bathroom sink stopper, even if it drains fine.
• Put a hair catcher over the shower drain.
• Look under the kitchen sink so you know where the P-trap and slip nuts are.
• Find the main water shutoff in your home.
• If you have teens, have them plunge the next clog with you watching (it’s on our teen life skills checklist).