Slow or Clogged Drain: How to Clear a Sink, Tub, or Shower Without Chemicals

Minneapolis Public Works says slow drainage in toilets, showers, and sinks is typically caused by clogs in the home's own plumbing, and only rarely by the city sewer. With one slow sink, tub, or shower, the clog is often on the stopper, just below it, or in the trap under the sink, and Liquid-Plumr notes that hair is a major component in most bathroom clogs.

This page separates a one-drain clog from a main-line problem, then lists the fixes from easiest to hardest. Poison Control advises buying a caustic product only if nothing else will do the job, so chemical drain cleaners come last. For a toilet, see toilet clogged and won't flush; for a kitchen sink with a disposal, garbage disposal not working. Weak flow out of the faucet is a supply problem, covered in low water pressure.

One Drain or Several?

Run water briefly in each sink, tub, and shower, one at a time, and flush each toilet once, watching the tub, shower, and any floor drain while you do. Stop at once if water rises anywhere else.

Only one fixture is slow. The clog is in that fixture's own drain, a homeowner job, and the rest of this page is for you.

Several fixtures are slow, or water comes up in a tub or shower when a toilet flushes or the washer drains. The blockage is farther down, in a drain line those fixtures share or in the sewer lateral, the pipe from the house to the street. Water that can't get past it rises at the lowest opening: LA County Public Works describes sewage from an obstructed public sewer backing up a home's drain line and out of the lowest fixture, such as a tub or shower. Stop running water and call a plumber. Portland Environmental Services says a plumber should find the cause first: a problem between the house and the street is the owner's to repair, one in the city sewer the city's. Minneapolis says to call the city if neighbors have the same trouble.

Most Likely Causes

1. Hair and soap scum on or just below the stopper. Drano says stoppers collect food, dirt, hair, and soap scum, and Liquid-Plumr describes hair clogs that form at or below the stopper.
2. A pop-up stopper that no longer opens fully. It slows the drain even with no clog. Moen's troubleshooting starts with the pivot rod, which enters the back of the drain under the sink; if it isn't broken, adjust it together with the lift rod.
3. Buildup in the P-trap. The U-shaped pipe under a sink holds water to block sewer gas, and Oatey, which makes them, notes that it also catches debris and solids. Liquid-Plumr says traps often clog with hair and soap scum, and that a ring dropped down the sink may be waiting in the trap.
4. Grease and food in a kitchen sink. Liquid-Plumr says grease cools, solidifies, and sticks to pipe walls, trapping other debris.
5. A clog farther down the branch drain. If the stopper and trap are clean, the clog is beyond the trap, where a hand auger reaches.
6. A blockage in the main drain or sewer lateral, when more than one fixture is slow. That is a plumber's job.

What You Can Fix Yourself

Work in this order and test the drain after each step. Wear rubber gloves, as Liquid-Plumr advises for stoppers and snaking, and bail a full basin into a bucket first.

1. Pull and clean the stopper. Drano suggests rotating a stopper, then pulling it up and out. If a bathroom sink pop-up won't come out, a rod under the sink holds it: Kohler says to unthread the nut where the rod enters the side of the drain, pull the rod out, and lift out the stopper. On a tub, Liquid-Plumr says a strainer usually lifts with a fingernail or a flat screwdriver; follow the maker's instructions and don't drop screws down the drain. Clean off the hair and scum, reassemble, and test.
2. Hook out the hair with a barbed tool. With the stopper out, push a flexible barbed strip such as the Zip-It deep into the drain, twist it, and pull it back out slowly. Zip-It says the barbs catch hair and debris.

3. Plunge it, with the overflow blocked. Use a cup-style sink plunger; Liquid-Plumr notes that a kitchen plunger is different from a toilet plunger. Drano's steps: leave enough water to cover the bottom of the plunger, block the overflow opening with a rag to help the suction, and push down and up a few times. On a double kitchen sink, Liquid-Plumr says to hold a wet rag over the other drain. Never plunge after a chemical cleaner.
4. Clean the P-trap (sinks). Oatey's steps: set a bucket under the trap bend, loosen the slip nuts, usually one at the sink tailpiece and one at the wall, and lower the trap to drain it. Clean out the trap and the connection points. For stuck metal fittings, Oatey suggests penetrating oil and gentle pressure, and says a badly corroded trap may be safer to replace. Reassemble with each washer's tapered side toward the fitting, hand-tighten the nuts, then add about a quarter turn with pliers; overtightening can crack plastic or strip threads. Run water for 30 to 60 seconds and check for drips. Tub and shower traps are out of reach below the drain, and Oatey's shower-trap steps glue (solvent-weld) the trap in place, so use the auger from above instead.
5. Run a hand auger. DrainX's steps: loosen the thumbscrew and feed the spiral head into the drain until you reach the clog, leaving 4 to 5 inches between the tool and the drain. Tighten the thumbscrew and turn the drum clockwise with the knob to drive the head farther in; some clogs need a counterclockwise turn. When the tool reaches the drain rim, loosen the thumbscrew, pull the drum back, and repeat. Reel the cable in and flush the drain with hot tap water, as Liquid-Plumr suggests after a clog clears. DrainX says its 1/4-inch auger is not for toilets: it can damage the porcelain and twist in the larger toilet drain.

Hot water, not boiling. Drano's Max Gel directions say to flush with hot, not boiling, water, and Drano cautions against boiling water on sinks with PVC pipes. Charlotte Pipe rates its PVC drain pipe for operating temperatures up to 140°F.

Chemical cleaners, if you use one. Never in a toilet or in a sink with a garbage disposal: Drano says not to use its clog removers in toilets, and InSinkErator and Moen say never to put chemical drain cleaners into a disposal. Elsewhere, follow the label exactly, use one product only, keep your face, children, and pets away from the drain, as Drano directs, and pour close to the drain: Poison Control says splash-back happens when a cleaner is poured from too high or too much goes into a completely blocked drain. If a disposal sink was already treated and didn't clear, don't turn the disposal on: Drano says the gel may splash back, and to consult a plumber.

When to Call a Pro

• More than one fixture is slow, or water rises in a tub or shower when a toilet flushes or the washer drains.
• Sewage backs up anywhere. Stop using water and call a plumber, or the city if neighbors have it too. New Bern's utility says to keep children and animals out of the area and to cut the power to it; flip that breaker only from a dry floor with dry hands, and never step into water that could reach outlets or cords (see our burst pipe guide). Portland suggests hiring a sewage cleanup company; if you clean up yourself, it says to wear gloves, boots, and protective clothing, keep sewage away from your face and eyes, cover cuts and wash any wound that touches sewage, wash surfaces with hot, soapy water, then disinfect with one part household bleach to ten parts water, and wash your hands well afterward. Don't mix bleach with any other cleaner.
• The auger doesn't clear it, or the clog keeps coming back. Liquid-Plumr's advice for tubs is to call a plumber for a recurring clog or one you can't clear.
• A chemical cleaner didn't clear it. Tell the plumber which product you used and when.
• Something solid went down and isn't in the trap. Liquid-Plumr says a foreign object needs a plumber.
• A corroded metal trap won't come apart or won't reseal.

Our DIY vs. hire guide puts plunging and clearing a P-trap in the DIY column and sewer main problems with a licensed plumber.

Prevent It

Put a hair catcher or drain screen on every tub, shower, and bathroom sink, and a strainer in the kitchen sink. Drano recommends screens on all drains, and cleaning bathroom stoppers regularly.

In the kitchen, keep fats, oils, and grease out of the drain. Portland Environmental Services says grease gets thick and sticky as it cools and builds up inside pipes. Scrape food scraps into the trash or compost, pour grease into a can and let it harden before throwing it out, and wipe pans with a paper towel before washing them. New Bern's utility adds that washing grease down with hot water doesn't work: it cools and solidifies farther down the line.

Frequently Asked Questions

How do I unclog a drain without chemicals?

Pull and clean the stopper, hook out hair with a barbed tool, plunge with the overflow blocked, clean the P-trap under a sink, and run a hand auger, testing the drain after each step.

Does baking soda and vinegar unclog a drain?

Don't count on it. Poison Control says the carbon dioxide they make escapes through the drain instead of building pressure, and the mix is unlikely to be strong enough for tough grease clogs. Never pour vinegar or anything else on top of a commercial drain cleaner.

Can I pour boiling water down a drain?

Not if the drain pipe is plastic. Drano cautions against boiling water on sinks with PVC pipes, and Charlotte Pipe rates its PVC drain pipe for up to 140°F. Use hot tap water.

Why is my bathroom sink draining slowly?

Often hair and soap scum, which Liquid-Plumr calls frequent culprits, on or just below the pop-up stopper, or a stopper that no longer opens fully. Clean the stopper, check the pivot rod, then clean the P-trap.

Why does water come up in my tub when I flush the toilet?

A blockage in the drain line they share: the water can't get past it and rises at the lowest opening. Stop using water and call a plumber.

The Bottom Line

One slow drain is a local clog: clean the stopper, hook out the hair, plunge with the overflow blocked, clean the trap, then run a hand auger. Use hot tap water, not boiling, on plastic pipe, and never plunge or snake after a chemical cleaner. If several fixtures are slow or water rises in the tub when a toilet flushes, stop using water and call a plumber.

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