Keep drains clear by treating them monthly with boiling water and 2 tablespoons of baking soda or, infrequently, with a liquid drain cleaner. These cleaners may also clear partially clogged drains. If you use a chemical cleaner, follow the directions and rinse the drain afterwards.
Caution: Chemical drain cleaners are dangerous. If you splash any on your skin, wash it off immediately in cold water. If a drain is clogged and the cleaner remains in the sink, call a plumber. Don’t try unclogging the drain by other means; the leftover cleaner may splatter you.
Using a plunger
If a drain is totally blocked, first try to free it with a plunger. Remove the sink stopper or strainer. Most wash basins have pop-up stoppers that can be removed by simply pulling them up. On some models, you must first reach under the basin and remove a nut that retains the ball joint and the pull control. If the sink has an overflow opening, block it with a wet cloth to prevent air from being drawn in as you work the plunger. Run enough water into the sink to cover the rubber force cup of the plunger.
Place the cup over the drain, tilting the cup to get rid of trapped air. Vigorously pump the plunger up and down 10 times to create a surge in the water trapped in the drain. On the last up stroke, lift the plunger abruptly from the water. If the water rushes out, you may have dislodged the blockage. Run more water into the sink. If it doesn’t go down easily, try the plunger again. Don’t give up-keep trying.
Working with the trap
If the above won’t work, place a bucket beneath the gooseneck trap under the sink. Unscrew the cleanout plug on the bottom of the trap with a wrench and let the water run out. Clear the stoppage by hand or with a bent wire coat hanger.
Replace the plug.
If there is no plug, remove the entire trap, which is held on by two coupling nuts. Remove the higher coupling nut with a pipe wrench. (Wrap the jaws of the wrench with tape to protect the chrome on the slip nuts.) Then support the trap and remove the lower coupling nut. Clean out the stoppage and replace the trap. Do not overtighten the fittings, or they may leak. Using a snake
If the clog is out of reach, try dislodging it with a “snake”-a thin wire with a coiled spring on the end. Use a flexible-bulb auger with a cable diameter of 1/4 inch. Crank the handle of the snake clockwise, both pushing into and pulling out of the drain. Rotate the snake into the drain, working it through the trap under the sink until it contacts and cuts through the stoppage. (You can distinguish between the mushy resistance of a blockage and the hard resistance of a bend in the pipe.)
If the clog is beyond the trap, work the snake into the drain pipe that leads from the trap into the wall. Run the snake through the cleanout or, if you have removed the trap, directly into the pipe. The snake works more effectively if it does not have to go around a lot of bends.
If the drain is still stopped up, the blockage maybe in a main drainpipe; call a plumber.