Q: I work in an elementary school as an occupational therapist. I work very closely with teachers in the school on Individualized Education Program legal documents, which need to be worked on collaboratively. I can do my part only if all the others do their part.

I have a coworker whom I work especially closely with, not by my choosing. Professionally, he is obnoxious, always waiting until the last minute to complete parts of the document that are required for me to do my part and terrible at staying on track during meetings. These are things I can handle. I can speak with him about these things.

Where I struggle is that his bathroom habits are disgusting. I have entered one of the school’s four adult restrooms immediately after him multiple times to find a toilet seat covered in urine and a toilet full of frothy pee. As someone who sits on a toilet to use it, this is unacceptable.

This is unprofessional, since this is a shared space, but it doesn’t necessarily rise to the level of bringing it up to my supervisor. What should I do?

— Anonymous

A: Disgusting. (Your use of the word “frothy” really sent me over the edge.) I agree that this is unacceptable.

And universal: Though the subject makes for a provocative advice column question, I’ll bet most of those reading this have had to deal with a coworker — known or unknown — with disgusting bathroom habits. And it can feel purposeful sometimes.

It feels that way to me, at least. Which brings me to this: I wonder if part of the issue here is that your colleague is passive-aggressively doing this deliberately. Does he seem displeased with his work? Is he hostile in other ways? You don’t seem to feel any hesitation about discussing your challenges with him professionally; I wonder whether it might be worth having a bigger, 30,000-foot discussion with him about whether he’s even happy in his job.

I agree that your colleague’s behavior doesn’t necessarily rise to the level of making an intervention from a supervisor necessary, but I also don’t think you should be expected to grin and bear it. Here’s my advice: Design and print four signs and tape each sign on the outside of the door of each of the four restrooms, or on the wall next to the toilet, where everyone can see them.

The signs should state plainly, and succinctly, that people who use the restroom are expected to clean up after themselves, which means flushing the toilet and wiping away bodily fluids so that surfaces are clean for other people.

See if that helps. You shouldn’t have to deal with a filthy work environment. And if your supervisor balks at saying something to the staff? You might have to take matters into your own hands (again) and send an email to your colleagues, explaining the situation and asking for their help in remedying it. At this point, you’re still not singling him out. But if THAT doesn’t work? Say something directly to the colleague. I’d do it in writing, not so much because you need to create a paper trail, but because the potential for your coworker feeling embarrassed is lessened with the distance offered by avoiding a face-to-face.

I encourage you to address this and not keep quiet.

Anna Holmes is an award-winning writer, editor and creative exec whose work has appeared in numerous publications, including the New York Times, Washington Post, and The New Yorker.