For the last few days there has been a smell in my bathroom that will not go away. The strongest scent seems to be under the sink when I open the door underneath. It is a strong musty smell. I pulled out the stopper and cleaned the hair out and flushed with hot water yet the smell remains. I don't know what else to do or look for. Any Suggestions?

Pour a 1/4 gallon of bleach down the drain and let it set overnight. Next morning flush it out with boiling water. If the smell still persists wash the inside of the cabinet out with full strength bleach. Good luck, Tom

I did the bleach thing entirely and smell is still there. I went under sink and took a smell right at pipe and seems smell is there. Also I ran water and there seems to be very slight leak at that area. Could this be related??

Bill, I suspect you have a very small leak in your trap or at the supply pipes. The water gets behind the wall or under the floor of the vanity and starts to mold. Can you remove all that good stuff under the sink and try to pry up the floor of the cabinet? If its mold or mildew buy a remover that has 2.4% sodium hydroxide.