[Ichneumon]

Yes, but if you look at that P-trap carefully, you'll see there is a segment of pipe above the trap but below the floor of the shower stall. Bacteria will build up in that segment of pipe and it'll stink. And if enough people in your family pee in the shower every day, it'll stink almost as bad as any public urinal.

ONLY if you never run water in the shower. But then, your point -- such as it is -- applies equally well to the trap in your toilet... If you never bother flushing.

But since that's not how people actually use toilets (or showers), your point is rather irrelevant.

If your argument were valid (and again, it's not) then showers would routinely stink up the house from the effect of bacteria on the grime and dead skin cells you wash off while showering. Try plugging up your shower drain and then letting your shower water sit there stagnating for a week or two... It's no rosewater either. But in actual use, your washing water flushes itself to beyond the P-Trap due to the clean water that follows it down the drain during a normal shower. And so does any other liquid that goes down the drain during the shower...

So you see my conclusion was indeed valid.

No, I see that your conclusion is still incorrect and based on misunderstandings about how the plumbing actually works under actual use.

[LibWhacker]

ONLY if you never run water in the shower.

Well, water runs in your toilet bowl, too, but I do hope you clean it out once in a while.

Bacteria will build up despite running water. And not just any bacteria, but the pathogenic organisms that thrive in raw sewage. Let's make a deal: You don't shower in my house and I DEFINITELY won't shower in yours!!!

But then, your point -- such as it is -- applies equally well to the trap in your toilet... If you never bother flushing.

No it doesn't. You're incorrect again. Your toilet traps bacteria completely below and behind the trap, unlike when you pee down the shower drain. I was going to post this diagram earlier, but figured everybody knew this stuff. I see I was wrong in that assumption.

As you can see, in a toilet, NONE of the long-term bacterial buildup is above the trap, unlike in your shower.

If your argument were valid (and again, it's not) then showers would routinely stink up the house from the effect of bacteria on the grime and dead skin cells you wash off while showering.

False comparison. We're talking about pathogens that grow in raw sewage. Do you want to stand in them? You want your family and your guests to stand in them? You want to wipe them on your towels when you dry your feet and track them across your floor into bed with you? Be my guest (just not at my house!).

But in actual use, your washing water flushes itself to beyond the P-Trap due to the clean water that follows it down the drain during a normal shower. And so does any other liquid that goes down the drain during the shower...

Hope you don't use that argument to avoid cleaning your toilets.

BTW, when WAS the last time you scrubbed out your shower/urinal drains??? Do your drains ever tend to back up while you are showering/peeing in them?

You see, it's not just the pee that is the problem. It's the smelly and dangerous pathogens that like to live in urine that you and your family and your guests are soaking in when that happens.

Don't argue. My logic is sound. And stop peeing in your tub, for Heaven's sake!