While we were travelling throughout China last fall, we encountered a large number of hotel bathrooms that just flat out stank. Not post-crap stink, but straight-up sewer stink. We soon discovered the problem: they don't have the S pipe here. You know the S-pipe, right? The little bend in the pipe underneath your sink which ensures that there will always be a little water in the pipe preventing sewer gasses from coming up. Despite the ubiquitous presence of high-tech cellular phones, flat-screen televisions, and now fleets of luxury cars, this staple of western plumbing has yet to catch on here.
Thankfully, the shower and kitchen drains of our new apartment seem to be thusly equipped (a non-smelling bathroom was one of our key requirements). Here is the interesting variation beneath our kitchen sink:
After a few days, however, we noticed a nasty rotten vegetable smell coming from somewhere in the vicinity of the bathroom. Soon after, we made a shocking discovery: our bathroom sink has no S curve. Fortunately, we can close the drain in the sink, but it just amazes me that such a basic (and oh so necessary) plumbing fixture continues to be left out of even fairly new constructions.
There is hope though - in Chengdu we noticed a public bathroom in which an enterprising plumber had seen the problem and devised a solution. He bent a loop into the pipe running down from each urinal.