We all know how showers work. We use shampoo to get our hair clean, and body wash to get the day’s grime off our bodies. We may even shave in there! And all that dirt and sweat and oil and hair wash safely down the drain… except it doesn’t.
Every time you shower, your drain is accumulating some of that nastiness as it binds with soap scum, which attaches to the drain and the inside of it. It’s why drains get clogged when you don’t keep them clean. It’s also why mold, mildew, bacteria and fungi form in your tub and around your drain, and chances are, they’re what’s causing all that stink.
“These are communities of microbes that grow over the course of days, months and years and over time can become almost impossible to remove,” says Jason “The Germ Guy” Tetro, author of The Germ Files. “As for what the smells happen to be, they are the off-gasses of metabolism, which are no different than our own version of off-gassing.” To put it in laymen’s terms, tiny organisms are basically farting non-stop in your shower.
“A typical drain will have numerous bacterial and fungal species that will generate different types of gasses,” Tetro explains. “Some will be unnoticeable, such as carbon dioxide. But others will come with a rather unpleasant odor such as sulfoxides [which smell like] onion or garlic; fatty acids [which are] sickly sweet; and esters, that can smell musty or grassy.”
He recommends using a brush to scrub inside the drain as best you can, followed by a combination of baking soda and vinegar, after which “a rather violent reaction takes place that can help to remove the biofilm from a surface.”
But if the smell persists — or if your drain smells uncomfortably like your toilet — there could be a problem with the trap that normally prevents sewer gases from rising up through and out of your water pipes. If that’s the case, there’s one nearly foolproof way to fix it: Call a plumber.