If you have standing water in your kitchen sink and turning on the garbage disposal doesn’t drain the water, then it’s most likely clogged with debris.
The first thing you need to do is SHUT OFF THE POWER at the main circuit breaker or unplug it from the outlet under the sink. To be sure that the power is off, test it at the switch to see if it runs by switching to the ON position. After checking the power, make sure to turn the switch back to the OFF position.
Once you have the power off, find an Allen wrench and get underneath the clogged disposal. There will be a hole directly in the center of the disposal. Place the Allen wrench in the hole and turn clockwise until you feel resistance. Once you feel resistance turn counter clockwise until you feel the resistance again. The resistance you are feeling is whatever is causing the clog, so in order to unclog it you need to knock it out. You should repeat the process until the resistance is gone.
When you no longer feel resistance, make sure the switch is still turned OFF and turn the power back on at the breaker or plug the disposal back in underneath the sink and get back underneath it press the red reset button. THEN flip the switch to ON and test it to make sure it was unclogged. Please note that if there is standing water or other debris in the sink this may spray out once it’s turned back on.
If you don’t feel any resistance when you turn the Allen wrench, then it may not be clogged; however, the drain pipe may be. This usually happens when the disposal was able to process the food, but it was too much for the pipe to handle. The problem has now moved further down in your plumbing.