Sewer Gas

I always try to come up with catchy titles that will make you guess what in the world is running through my head when I write these blog entries. In the case of this entry, it is no mystery: I am writing about sewer gas. And not because I’m on a bathroom kick either! The toilet paper entry has nothing to do with why I’m writing about sewer gas now.

The newly arrived freshmen are why I’m writing about sewer gas. It is not that they stink like a sewer; it is because the dorm building I live in is now full of students. As opposed to when I first got here, when only about 1/3 of the building was occupied.

I live on the ground floor, and every time someone anywhere on the floors above me flushes the toilet I hear it… and smell it. This was at the height of the summer’s heat, when all of my windows hung open, and I would leave the bathroom door open to coax the breeze through my apartment. At first I thought the sewer stench was coming through the open window in my bathroom, but then logically it would also come through the kitchen window as they both faced the same direction, right? There was no stench in the kitchen, just the bathroom.

At the start of the day things were not really bad, but as the day wore on the smell became untenable. It would come and go throughout the day, and intensify after 5PM. After fervent cogitation I married the school’s teaching schedule to the stench: students have a 2 hour break in classes between 1PM and 3 PM; and classes let out for the day at 4:45 PM. During the break and after 5 is when the smell was the strongest.

Another nugget of information: my next door neighbor, Victor reported an invasion of mosquitoes in his apartment, and he was also plagued by a sewer gas stench. Two apartments, same smell, mosquitoes coming from somewhere, windows screened… what could it be?

In desperation I started closing all of my drain plugs: bathtub, sink and toilet bowl lid. No help. If anything, the problem intensified. I thought about taking the issue up with the maintenance man, but I decided against it for several reasons. The smell comes and goes, and it might not come at all when he is here to see about the problem. But more importantly: Chinese people are used to living with terrible smells. That sounds bad and I don’t mean it as a slam to the Chinese, but they would see this sewer gas problem as just one of the vagaries of life and not attempt to find the source and fix it. So I took it upon myself to do so. I had had enough of the stench, especially if I was to be confined to my apartment in the evening hours, when the smell was particularly bad (and the maintenance man was off work).

You know, how you track a smell by sniffing repeatedly? I can personally testify that sniffing out the origin of sewer gas is not a pleasant experience. But it only took a few dedicated sniffs to find the origin.

From the floor under my bathroom vanity juts an open drain line that measures about 3 centimeters in diameter, and it extends approximately 20 centimeters up. Into this open drain line drops a clear flexible tube that comprises the drain line for my bathroom sink, and it runs in a straight line downward.

Open sewer line. No P-trap. No brainer.

For those of you who don’t know, P-traps are a clever plumbing design meant to trap sewer gas. For some reason the gas cannot navigate the deep S-curve of the P-trap, thus drain lines with such a configuration do not emit such an awful smell.

Job 1: cap the open drain line. It just so happened that, the week prior I had bought two plastic containers to serve as condiment holders. They were not effective in that capacity, but it looked like their lids would serve nicely as a sewer line cap. Trying it out I found that that was in fact the case: the circumference of the lid is approximately ½ centimeter larger than the sewer line.

Next problem: cutting a hole for the sink drain line. Not such a problem after all! Starting with the vent hole pre-made in the lid itself, I measured and cut a 1.5centimeter circle out and forced the flexible tubing into it. Even though the hole I made was not perfectly round, the tubing fit into it nicely. Now I just needed to fashion a P-trap. Again, a chinch: the flexible tubing allowed any configuration desired, and a wire tie around 2 of the 3 loops of the tubing held it in place.

Would my repair stand the test?

With a few minor adjustments, it worked like a top. I gave my homemade sewer cap and P-trap configuration a one-week trial to see if the smell of sewer gas would dissipate, and then watched (sniffed) for more manifestations. There were none. I was satisfied that I had solved my sewer gas problem.

Now for Victor, who also had the stench plaguing his apartment. Victor is gone more than he is home; he has friends in another part of town and usually stays away unless he has an early class. It took me a few days to catch him at home, but when I did I asked him if he was still plagued with mosquitoes and a bad smell. I listened to him rant about it for a few minutes; he even confessed that he had cornered our advisor about it to no avail: Sam thought that Victor’s apartment smelled bad because Victor was never home.

I then told Victor about my discovery and subsequent fix. I also told him that the mosquitoes were breeding in the sewer line and coming up through that pipe. He sounded very skeptical until I invited him into my apartment and showed him what I was talking about: the jutting sewer line (mine now capped) and fashioning a P-trap.

Just the smell in my apartment convinced him. Or, I should say: the lack of smell in my apartment convinced him. In the spirit of generosity I gave him the lid from the other container I had bought and instructed him on how to cut a hole for the tubing, and then on how to make a P-trap. Victor was sincerely impressed and ran straight to his place to make a sewer line cap and a P-trap. On his way out, he grudgingly commended me on my good thinking.

Now he knows I’m not just a ‘girl next door’ type. Looks like I blew it again!