Project Guide

How to Unclog a Sink

Use Boiling Water to Dislodge the Clog
Use boiling water to dislodge the clog
  • Over high heat, bring a half gallon of water to a rolling boil.
  • Remove any standing water from the sink.
  • Carefully remove the water from the stove and pour directly into the drain in a steady stream.
  • The water should begin to drain; if it does not, allow the water in the sink to cool completely, then repeat the process one more time.

Tip: Do not use this method if the drain is attached to PVC pipes. Boiling water could soften or damage the material.

Inspect the Garbage Disposal
Inspect the garbage disposal
  • Turn on the garbage disposal; if the clog is in the disposal, running it may break it up. 
  • If the disposal is not running, check to see if it has overheated. Activate the reset switch at the side or on the bottom of the unit. Then turn it on again, to see if this clears the clog. Click here to see our guide on How to Fix a Garbage Disposal.
Dissolve Clog with Baking Soda Mixture
Dissolve clog with baking soda mixture
  • Pour one cup of fresh baking soda down the drain, followed by one cup of white vinegar 
  • Place a rubber stopper or other cover over the drain opening. 
  • Wait 15 minutes, then take out the drain cover and run hot tap water down the drain to clear the clog.
Use a Wet-Dry Vacuum
Use a wet-dry vacuum
  • Set up your wet-dry vacuum for wet use. Follow the manufacturer’s instructions. 
  • Place the hose end at the entrance of the drain, then create a tight seal around the end of the hose and the drain. 
  • If the clog is on one side of a double sink, seal up the opposite side of the sink with a rubber stopper. 
  • Turn on the vacuum to the highest setting. The pressure of the vacuum should dislodge the clog. 
  • If this does not work, try the next technique.
Use an Auger on the Upper Part of the Pipe
Use an auger on the upper pipe
  • Feed the cable from the auger (also called a plumbing snake) into the drain opening until you meet resistance. 
  • Once the end of the cable is touching the suspected clog, pull out an additional one foot of cable from the machine end and hold it as slack. 
  • Lock the length of cable, then begin turning the crank on the device. The cable will bore into the clog and push forward; pull put more cable if needed. 
  • You should be able to feel a change in resistance once the auger has broken through the clog. Retract the auger, then flush pipe with hot water from the tap. 
  • If you don’t meet any resistance, the clog may be further up the pipe in the branch drain.
Use an Auger on the Trap and Wall Pipe
Use an auger on the branch drain
  • Go under the sink and place a bucket under the pipe to catch excess water 
  • Unscrew the connectors on the PVC pipe that holds the trap (the curved piece of pipe) to the vertical and horizontal drain pipe. 
  • Check the trap for clogs. If you can remove debris from the trap, reconnect it, then run water into the sink. If the sink does not drain, the clog may rest farther up the pipe. 
  • Remove the horizontal pipe that connects to the pipe in the wall. 
  • Feed auger into the wall pipe as describe above. 
  • When you have removed the debris, reassemble the pipe and trap and hand tighten the connectors. Do not over tighten as the plastic connectors might crack. 
  • Flush the sink with hot water; the water should drain quickly. Be sure to check under the sink as the water flows to be sure there are no leaks. 
  • Dry the area under the sink carefully after you have finished your work.
Take Measures to Prevent Clogs
Take measures to prevent clogs
  • Don’t overload the disposal. Grind no more than 1 cup of food waste at a time and do not put any inorganic matter down the drain. 
  • Do not allow grease, oil or coffee grounds to run down the drain or go through the disposal. Collect this waste in disposable containers or bags and remove them to an outdoor receptacle, or in the case of coffee grounds, place in a compost pile. 
  • Freeze a mixture a half vinegar and half water into ice cubes. Periodically drop one or two of these into the garbage disposal to keep it fresh. The ground ice and slight acidity will also help scrape away buildup inside the disposal and the pipes. 
  • In the bathroom, use a screen or grate over the drain to help catch hair and soap scum. Clean out the grate after each use. 
  • In the kitchen, run hot water from the tap after each sink use to help keep the drain cleared.