How To Unclog a Kitchen Sink Drain
The kitchen sink has a drain at the bottom of each basin. One drain typically leads to the garbage disposer and then on to the drain pipe. The other basin has a strainer to stop debris, water bypasses the disposer and goes straight to the drain pipe. If you have a dishwasher, it typically connects to an air gap mounted above the sink and then on to the garbage disposer.
A slow drain in the kitchen can often be resolved by running the garbage disposer. If the water begins draining from the sink, turn on hot water and let the disposer run for 30-60 seconds. If the disposer makes no sound, it may need to be reset by pressing the reset button on the bottom, underside of the disposer. If the disposer makes a sound but won't turn, turn it off and use a the manual crank wrench (a 1/4" Allen wrench will also work) to turn the impeller a few turns. Remove the wrench and try the disposer again.
Now if you still have a clogged sink, you might be thinking of using chemicals - Don't. Some chemicals can damage pipes, the environment or you if you get splashed. If you have to work on a drain after a chemical has been added, it makes the work harder and more hazardous. Additionally, most chemical drain cleaners don't work that well. Running hot water through clear drains is the best way to keep them clear. Skip the chemicals.
If water drains from one basin but not from the one with the disposer, the clog is in the disposer or the pipe immediately after it. If the basin with the disposer drains but not the other, it is small clog in the section of pipe leading from the strainer to the drain pipe. If neither side will drain, then the clog is probably in the "P" trap or farther along in the drain pipe. If the clog is affecting other fixtures, such as a bathroom or laundry room, then the clog is more serious and located in a branch drain line or main drain. More serious clogs should be addressed from clean outs designed to give access to branch and main drains. These are typically found outside or under the home.
If you believe the clog is local to the sink, you can use a plunger, an auger or a blow bag to grind or push out a stubborn clog. We like the effectiveness of blow bags, but lets start with the old-standby, the plunger. For a sink, use a standard model without a flange, like the one below.
When plunging, there must be some water in the fixture, so add water to cover the business end of the plunger. Tilt the plunger cup to burp the air as it is submerged in the water. Place the plunger over the drain and completely cover the drain opening. With the plunger completely under water, press and pull it rapidly for 15-20 seconds. If the water drains out of the basin, add some more water and plunge again. If the water seems to be properly draining, go ahead and run some water to test the drain.
An drain auger, a smaller version of a drain snake, can be inserted down the drain but you must remove the P-trap fitting beneath the sink and insert it there. The advantage is that if you are driving the auger deep into the drain line, there will be less friction than if it has to weave its way through the trap before reaching the drain line. To remove the P-trap, simply unscrew the two collars at either end of the "U" shaped pipe. Insert the drain snake as far as you can, then turn the set screw tight to hold the auger cable and crank the handle (or use a power drill on some models). As you crank the handle the auger tip grinds at the clog. Continue to insert to auger cable as far as it will go. If the auger gets stuck, reverse the direction of cranking and pull gently on the cable to extract a short length. Then resume forward action.
The last method, our favorite because it has worked so well for us in the past, is the blow bag. Picture a heavy duty balloon that screws onto the end of a hose. Picture a balloon with holes on the other end and that it is small enough to fit into a pipe. After removing the "P" trap, slide the blow bag as far as you can, into the pipe under the sink and turn on the hose. The first thing the bag does is inflate with water until it is securely wedged in the pipe. Now water starts spurting out the other end to blast away at the clog. Leave it on for a while and the force of the water will push the clog all the way out to the main sewer line. To remove it, turn off the water, wait a few seconds for it to deflate and then gently pull it out from the drain. Reconnect the section of pipe removed earlier and you should have a clear running drain.