We have a stand up shower, no septic tank, city sewer system, first floor in a private home. This is the guest bathroom and has never had this smell before. The bathroom has really never been used very often either. Just recently, someone has been using the shower on a regular basis, and now the drain has a strong smell. The drain is not clogged at all, drains very fast. Should I call a plumber, or is there a way to fix this - is this hair/soap or something else all together. No other smells coming from the sink in the bathroom or the toilet.

Most bad oders in bathroom drains come from rotting hair mixed with grease from the soap. Try this. Tonight before you go to bed pour 1/2 gallon of bleach down the shower drain and let it set overnight. Next morning flush it down with a few large pans of boiling water. The bleach will start to dissolve and soften the hair and make it slippery and the boiling water will melt the grease and flush the mess out into the main. Now see if that smelly drain doesn't smell sweeter? Hope this helps but if you still have a odor I would snake the drain and then do the bleach thingy again. . Tom