Adventures in Hunting Foul Odor(s)

JEROME GROOPMAN, MD, author of the bestseller How Doctors Think, points out that even smart minds can easily be led astray by well-known cognitive biases. He teaches that during a diagnosis process, it's important to ask three procedural questions:

• What else could it be?
• Could two things be going on to explain the symptoms?
• Is there any relevant evidence that seems not to fit with the working diagnosis?

This post applies such questions to diagnosing (and treating) a mysterious stench in our school building. 

Upon probing, it seems our building’s denizens have actually been enduring at least 2 odors at the same time.…

In late July 2021, our new preschool director, Tatiana Zaidman, had called my attention to a “dead animal” smell in the closet of Classroom 3 (the northwesternmost room). So I suggested that she consult the pest control rep. After all, they’re used to dealing with dead mice/rats — and so might not only be able to identify the kind of smell, but also know how to make it go away. When I didn't hear more about the issue, I assumed that the exterminator had resolved it.

However, the exterminator did come out and inspected in the vicinity of the closet — but didn't find anything. I heard about this seven months later, when I met with Ellie Laycook, our interim administrator (Feb. 28 of this year). She told me that not only had the closet odor persisted, but also it was now evident also in the adjoining adult restroom (!). And there, it had taken on more of a sewer smell.

When I consulted with Tatiana again, she echoed that the stench had been ongoing and had spread. Furthermore, she noted that a deadline for dealing with this odor was nearing:  

We are preparing to use that bathroom to open our second classroom. When we reopened this year, we had one class that used the one other bathroom. Next year we will have two classes and will need to use both bathrooms.… This bathroom will be a children’s bathroom. It needs to be READY TO USE BY JULY 1st.

In short, since March — and now under some pressure to take action — I have faced a rather daunting diagnosis (and treatment) task. 

The Evidence — and the Likely Culprits

After I asked: When was the odor first noticed? I concluded that we seemed to be dealing with at least two different odors — one in each of the adjoining rooms. For Ruben (our custodian) said that the closet’s odor had been around for 2–3 years (!); the restroom’s odor, less than a year. The closet’s odor was musty, whereas the restroom’s was like stale urine. The former was constant, whereas the latter had grown in its strength and frequency over time. Furthermore, Ruben said, the restroom’s distinctive odor was more evident after people used the toilet.

For managers of old structures, an extremely thorough (and free) resource is inspectapedia.com, an online encyclopedia about buildings — with articles on (among other things) how to systematically diagnose, test, identify, and cure or remove a wide range of obnoxious odors in buildings. 

https://inspectapedia.com/odor_diagnosis/Odor-Diagnosis-Cure.php

https://inspectapedia.com/odor_diagnosis/Odor_Diagnosis_Steps.php

https://inspectapedia.com/odor_diagnosis/Odor_Diagnosis_Checklist.php

I learned that given that a restroom was involved, the first possibility to explore was the presence of sewer gas, which would be due to a faulty seal with one or more drain lines. 

If the sewer gas odor is traced to the plumbing drain/waste/vent system then you need the help of a licensed plumber to correct the problem.… Improper venting of plumbing drains, vent or sewer piping leaks, even a loose toilet can be a cause of the problem.

https://inspectapedia.com/septic/Sewer_Gas_Odors.php#SGSources

Then I noticed that in the restroom in question, there was a urinal hidden behind a false wall (!). I asked Johanna Schmidt, a previous chair of the B&G Committee, about it. She recalled:

I think that the Preschool Director at the time had taken on that project, and I think the reason they had removed/covered the urinal had something to do with dedicating that bathroom as a children’s bathroom so that they could meet some policy requirement from the state for licensing for the preschool. I don’t know specifically what happened to the urinal. There had been several requirements at the time that the state licensing agency had directed, for the purpose of expanding the preschool to include children under age two. 

This was a helpful explanation, for it cast the hidden urinal as a prime suspect. From my reading up on sewer smells, I had learned that a dried-out P-trap is a common culprit. The role of a P-trap is as follows:

Its primary purpose is to provide an airtight seal that prevents sewer gases from releasing into [the building’s interior space] through the drain line. 

The share of drain water that's retained by gravity in the trap’s P-shaped curve is what forms the seal that keeps out those smelly gases. But predictably, in an abandoned urinal, the trap’s reservoir of water would eventually have evaporated — thus allowing sewer gas to escape thereafter.

Furthermore, from the adjoining toilet stall, I could just make out the underside of that urinal. There was a brownish residue of liquid that had run down the wall beneath it. 

This suggested that the gasket at the urinal flange was also leaking (and allowing sewer gas to escape). For background on those components, see: https://youtu.be/dmSR99p21Bw 

The Treatments

In deciding how to proceed, I adopted a gradual, iterative approach: We would treat first for the most likely (and least expensive) cause. If the odor(s) went away, then we were done. If not, we would take further action, in order of likelihood.

Ellie agreed with my recommendation that Mishkon have a plumber remove the hidden urinal and cap off both its water supply and its drain. A urinal is not made to be sealed off behind a wall—and one could say that it had been protesting its mistreatment via the odor it was apparently generating. 

Ruben first removed (well, demolished) the plywood cover over the urinal, revealing the frame behind it. 

The plumber came while the preschool was on its Passover break. Here are photos of his handheld detector for combustible gases, with its nose held against the restroom wall at the urinal drain: before and after testing. Red lights show the detection of sewer gases. This was expected, given the brown residue running down the wall. Yet it’s nice to see corroborating evidence.

The plumber then disconnected the fixture and hauled it away at no extra charge. (It occurred to me that we might want to keep it for possible reuse during a restroom renovation, but where would we stash it in the meantime?)

Yet the next day, there was still a lingering odor in the restroom. So two treatment steps were then taken in parallel. The plumber and I (and Ellie, upon our recommendation) agreed that pulling up the toilet was warranted. We wanted to make sure that its drain seal (a wax ring) had not deteriorated or been improperly placed, allowing sewer gas to escape.

Although the gas detector didn’t find evidence of a leak around the toilet, there were two other circumstantial pieces of evidence that the wax ring was perhaps not sealing properly: the plumber observed mildew around the base of the toilet bowl; and when Ruben and I examined the subfloor under the toilet from inside the crawlspace, I had found soft wood that was evidence of rot — which suggested a water leak at some point. Unfortunately, I was not aware of records that would tell us when that toilet drain’s wax ring was last replaced, or if the rot had been noticed previously. (We do need a log like that, don’t we?)

In the meantime, it turned out that while repairing a known leak from the toilet’s flushometer (flush valve), the plumber told us that he needed to dismantle the valve assembly. That reduced the marginal cost of resetting the toilet at the same time by $65. We took advantage of the unexpected “bargain” opportunity and had the wax ring replaced, too. (And Ruben cleaned around the hole.)

Under the toilet, before cleaning

The other, parallel treatment step taken was that Ruben cleaned up the residue on the wall and floor of what had escaped from the urinal drain’s flange. It was reportedly pretty stinky in its own right. (Thank you, Ruben!)

As for the classroom’s closet, Ruben pulled out everything that had been stashed on its tile floor, so that the floor and baseboards could be inspected. The area looked okay: nothing suspicious was visible to my eye. So I got down on my belly and crawled across the floor, sniffing as I went, from one baseboard to the other. To my surprise, I actually found something: a patch of nondescript, dark brown crud, maybe a half inch wide and two inches long, that smelled like a dead animal when I put my nose up to it. I have no idea what it actually was. But late last week, Ruben dutifully cleaned it off, even pulling away the baseboard nearby and cleaning behind it, too. (Thank you, Ruben!)

The upshot? We may now have actually solved the problem(s). Ruben told me on the phone this morning, “I don’t really notice [a stench] anymore.” And likewise this afternoon, Ellie wrote to me:

I was in the building a couple days last week and today. The smell seems to have dissipated. Yay!!

In sum, after the above measures were taken, there’s apparently no longer a need for Ruben to be daily spraying Febreeze either in the restroom or the closet. Still, I am waiting to hear what Tatiana says when she returns from her 2-week break. She is a “customer” who also needs to be satisfied in this case.