If you suspect your air mattress has a small leak, you don't have to fuss with messy soapy water or baby powder. Find the leak in your air mattress in minutes using a small piece of tissue paper, foil or facial tissue. After you find the leak, use the patch kit that came with your air mattress to patch the leak. The whole process should take only a few minutes.
Inflate the air mattress to maximum capacity and place it on the floor.
Turn off the TV, radio, fan and anything else that makes noise. The room should be totally quiet and free from breezes.
Place a small piece of tissue paper flat on top of the air mattress, starting at one of the corners.
Put your ear near the tissue and listen for a hissing sound. If you don't hear hissing, the leak is not under the tissue. Make sure you put your weight on the mattress to help push the air out of the leaking hole. This will make it easier to hear the hissing.
Continue moving the tissue in a systematic way over the air mattress, placing the tissue paper and listening for the sound of air escaping. After you have checked one side of the mattress, flip the mattress over and check the other side. Don't forget to check the sides of the mattress, too.
When you hear a hissing sound, you have found the leak. Lift the tissue to see if you can see it. If you can't see it, move the tissue around to locate the exact spot where the air is coming out and mark it with a marker.