Fungus Amongus?

My apartment is on the bottom floor of the building in damp, humid, rainy Seattle. When I first moved in I noticed a rather offensive odor emanating from the sinks. I thought it was the drains so I had the landlord come by and clean those up, no help. So I've been lighting smelly candles and keeping the windows open(a little chilly now that it's October) while researching what else could possibly cause it. Almost every site I went to on the Internet agreed that it was the wood under my sinks rotting. Well, I'm a very busy man and haven't gotten around to informing the landlord of this. I have developed a new sense of urgency though after returning to my apartment after a weekend away to discover mushrooms growing out of the base of my bathroom sink. I couldn't believe it!! Sure my bathroom is woodsy, bamboo plant on the sink, leafy rugs, green towels, but I really didn't need any decorating help from my little fungusy friends. Visitors beware, I have implemented cost-cutting measures so those mushrooms on the salad I make you next time you're here may be home-grown....... :)