Has there ever been a study on the growth of bacteria in bathtubs when the dirty water has been left in it? My husband -who takes baths, not me- has a habit of leaving the water in the tub overnight and it gets so slimy, I’m sure it’s unsafe just being in there and breathing in the spores.
IANA microbiologist, and know of no studies, but I know a bit about the slime.
When your husband is in the tub, his motion keeps whatever is dissolved in the water suspended. This will include dirt, dead skin, an emulsion of soap and skin oils, etc.
When the motion stops, the heavy stuff (dirt mostly) starts sinking, and the lighter stuff (soap, skin oils, dead skin) floats upward. Given enough time, the separation is fairly complete (think bottled vinaigrette salad dressing) and there will be a layer of mostly slimey stuff at the top of the water. It is there because it is lower density, not because it grew there.
The fact that it is slimy would tend to keep it from shedding spoors and whatnot even if they were present.
Some of the really nasty stuff that can grow in water is anaerobic bacteria, and grows not at the surface, but lower down, when the surface is covered by an air tight barrier such as oil…but that takes at least days, not hours. This is what causes the “rotten egg” smell of truly dank water.
But what the heck is up with your husband? I’m a total slob, and even I have been trained to clean out the tub after a bath. Even if it is not a bio hazard, it’s nasty and gross. Make him stop it!
Spores? Is your husband a mushroom of some kind?
My husband is an army soldier, some imes he has really important things on his mind, and other times he is just plain tired.
Too tired to pull the plug? I can understand not waiting for it to drain and then scrubbing it down, but not spending two seconds to pull the plug? No excuse. It’s the bathtub equivalent of not flushing.
Just to add a note of support: we used to leave the evening shower water in the tub overnight during the winter to help keep the house humidified. By morning, it was cold, and the people that showered in the AM would drain the tub and shower. It helped to keep the upstairs warm, too - that’s a lot of btu’s that you’re letting drain away.
A question for the OP - what process do you think would be going on in the tub overnight that was not already going on on your husband all day long? When he gets home, but before he has bathed, presumably you do not think that he is shedding unsafe spores. When he sluices off some modest percentage of those germs, dilutes them a millionfold in bath water, and then goes to bed, do the germs not continue to multiply on him as well?
You’re wrong.