Here’s a tip sheet listing a few methods to clearing out drains in the kitchen sink (plugged bathtubs can benefit from these too). At the bottom you’ll find a suggestion for monthly maintenance and a homemade recipe to keep them as trouble free as possible.
- Baking Soda: Remove as much of the liquid that’s backed up as you can. Toss 1 cup of baking soda into the drain then pour a large pot or kettle of boiling hot water over top. If it empties completely, pour down another kettle to give it another hot flush and then let cool water run from the tap for a couple minutes.
- Vinegar: Tried and true method: Remove as much liquid as you can. Toss in 1 cup of baking soda, then pour down a cup of household vinegar, plug with the stopper then let sit for half an hour. After about 30 minutes, unplug and pour a kettle full of hot water on top. See this page from thegoodhuman.com  and this this one from treehugger.com  for more details. This is the method I’ve grown up with and it works even if there’s still liquid backed up (although it works faster without water). Just double the baking soda & vinegar amount, give it about an hour and things have fully emptied, dump more fresh batches of boiling water 2 or 3 times to completely clear out the gunk.
- Plunging: Use a small plunger to try forcing things to clear. You’ll need a few inches of liquid in the sink to help make a vacuum seal for the plunger and a few forceful plunges to make this work. You can buy a plunger that’s about a 1/3 of the size of a regular toilet plunger. These are only a couple bucks, need very little room and they’re great to keep just in case trouble rears. You can use a full sized one if you can’t find a small one.
- Poking & Taking Apart: Remove the trap or clean-out plug underneath the sink to try clearing the blockage. Use a plumber’s snake or a wire coat hanger to poke down and break apart the mass. You’ll need an empty bucket on hand to catch all the liquid as well as eye goggles firmly in place.
- Desperate Situation & Water Won’t Empty: Chances are if you do a treatment with baking soda and vinegar, have the stopper removed, and leave the backed up mess overnight, you’ll find the liquid should have emptied by the morning. The vinegar and baking soda should have worked some of the buildup free on its way down. Do a hot water flush first thing and if the liquid empties as quickly as it normally would, you should be ok–do a couple hot water dumps though just to make sure. However, if the liquid empties slowly, you might want to check the trap to make sure there’s no mass blocking it. If there isn’t, try a couple more treatments of the Flush throughout the day. You just might get away with not having to call in the plumber.
- Sluggish or Slow: If you notice that things are emptying slower than usual but it’s not completely clogged or backed up yet, do the “Flush” technique right away to prevent a full blockage. Make sure to finish off with a few more hot water dumps.
If you’re dealing with is a double sink, make sure to insert the stopper on one side, then work on the other side.
Be careful if using chemical commercial products, wear eye goggles since the liquid can splash back up at you. If you’ve used a commercial product and it didn’t clear out the clog, call a plumber. You don’t want to add anything to the backed up liquid that might react badly to the chemicals in the cleaner. Also don’t try removing the trap since the chemical water can splash into your eyes and face. A professional is better equipped to handle this situation.
If it’s a bathroom sink that’s slow to empty or plugged with hair and ickies, here’s a good video showing you step-by-step how to fix that up…
Once a month clear things out with baking soda and hot water or the vinegar, baking soda and hot water flush. Here’s a recipe you can mix up in big batches and use monthly too:
1 part baking soda
1 part salt
1/4 part cream of tartar
- Pour 1/4 to 1/2 cup of this mixture into the drain and dump a kettle full of boiling water. Run hot water from the tap for a couple minutes, then turn to cool and run for another couple minutes. Do this monthly to clear out any fat, grease and nasties buildup that may be beginning to form.