How to Unclog a Sink Drain

  • 01 of 06


    Bathroom sink and mirror
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    Occasional sink, tub, or shower clogs are a fact of life, and are usually caused by localized clogs in just a single sink trap or branch drain. However, if you have several fixtures that are draining slowly or not draining at all, the problem may be in one of the main drain stack or sewer lines in your home. In this tutorial we'll also discuss the right plunger or auger to use for sinks (versus toilets) and what to do if the clog is a bit more stubborn. 

    Difficulty Level:

    • Easy

    Tools...MORE and Materials You Will Need:

    • Cup Plunger
    • Wash cloth or duct tape
    • Sink auger (for stubborn clogs)
    • Channel-type pliers (if needed)
    • Bucket (if needed)
    Continue to 2 of 6 below.
  • 02 of 06

    The Easy First Approach: Boiling Water

    Close-Up Of Water Boiling In Teapot
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    The Easy First Approach:  Boiling Water:

    Most clogs in sinks and tubs are due to a combination of hair, grease, soap residue, and tepid water. If you have metal pipes, then try hot water—very hot. With metal pipes, try pouring boiling water down the drain. This may well dissolve the grease and soap residue and restore your drain to full operation. Note: hot tap water will do nothing to dissolve the clog, since it is simply not hot enough.

    CAUTION: Do not pour the boiling water directly on a...MORE porcelain sink, but rather down the drain. And do not use boiling water if you have plastic PVC pipes, since water hotter than 175°F.  can soften some types of PVC pipe. For plastic pipes attempt to clear the clog using a plunger.

    1. On your stove, boil a gallon of water in a large pot or tea kettle.  
    2. Carefully carry it over to the clogged sink.
    3. Slowly pour the boiling water into the drain (not directly onto the porcelain), and see if it dissolves the clog.
    4. If not, proceed to the next step, which uses a plunger.
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  • 03 of 06

    Attempt to Clear the Clog Using a Plunger

    Plumber unclogging kitchen sink
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    Attempt to Clear the Clog Using a Plunger:

    There are two basic types of plungers, the cup plunger and the flange plunger. For working in sinks, showers, and tubs, use the cup plunger. The flange plunger is specially shaped for toilet use. Also, for sanitary reasons, you don't want to mix the two.

    1. First, if this is a lavatory sink, seal the sink overflow outlet found at the top of the sink bowl, just under the rim. Use a piece of duct tape to cover the sink overflow hole. Another approach is to...MORE block the overflow opening with a damp cloth. 
    2. For best results, also duct tape the bath tub overflow, if there is one in the room with the clogged sink.
    3. If the clog is in a kitchen sink, remove the basket strainer. If the clog is in a bathroom sink, remove the drain stopper. Try lifting it out or turning and lifting.
    4. Fill the sink bowl halfway with water.
    5. Place the cup plunger over the drain hole and make sure it has a good seal against the sink surface.
    6. Using quick, sharp plunges, attempt to clear the obstruction with the plunger and check for drainage. You may need to hold your hand over the duct tape or wet cloth sealing the overflow opening—the plunging motion may cause it to loosen. 
    7. Once cleared, let the faucet run for several minutes. Remove the overflow outlet seal and replace the drain stopper or sink basket.
    8. If the clog did not clear, proceed to the next step.
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  • 04 of 06

    Use an Auger for Stubborn Clogs

    drain pipe auger

    Use an Auger for Stubborn Clogs:

    If the plunger did not clear the clog, other tools are available, such as a sink auger (also called a drum or canister auger), or a drain-cleaning snake.

    Of these, the sink auger is preferred for its clean ease of use and convenience. For less than $20, it's a handy tool for all drains except the toilet.

    • With the lavatory sink stopper removed, extend the auger cable into the drain. When you feel it against the clog, pull out about 12 inches more of the cable and...MORE tighten the set screw.
    • Turn the crank handle of the auger with firm but gentle pressure.
    • Extend more cable as required until you feel you've worked through the clog. This should work if the clog is in the trap.
    • Repeat and then flush with hot water from the faucet once the drain starts to flow.
    • If you have extended more cable than the distance through the trap, then the clog is beyond the trap, probably in the vertical vent stack in the wall to which the drain is attached. To get at the vent stack, see the next step as it involves removing the waste trap.
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  • 05 of 06

    The Auger and Removal of the Waste Trap

    Water leak - flood in the bathroom.
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    For clogs beyond the trap, getting to them is a bit more work but still fairly easy.
    • Place a bucket under the trap to catch the water that will come out once the trap is removed.
    • Loosen the slip-nuts at each end of the trap with a pipe wrench or channel type pliers.
    • Remove the slip-nuts and the trap. Note how the possible nylon washers are oriented.
    • Dump the water in the trap into the bucket. Water will also drain from the disconnected ends.
    • As in the previous step, extend the auger cable into the...MORE flat section of drain pipe. When you feel it against the clog, pull out about 12 inches more of the cable and tighten the set screw
    • Turn the crank handle of the auger with firm but gentle pressure.
    • Extend more cable as required until you feel you've worked through the clog.
    • Reassemble and flush the drain with hot water from the faucet to clear any remaining debris.
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  • 06 of 06

    What About Chemical Drain Cleaners?

    Pouring chemicals down a sink
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    Don't use them. Chemical drain cleaners are no friend to the environment or the drain pipes your plumbing system and can be very dangerous to use. I strongly recommend you use the manual cleaning techniques outlined in this tutorial instead of caustic chemical cleaners.

    Chemical cleaners rarely work on stubborn clogs. After you try to use the caustic cleaner and it does not work, you are then left with a sink full of toxic chemicals that need to be bailed out by hand into a bucket and flushed...MORE down the toilet. Yuck.