Nathan, I think you've missed some posts, but regardless I think what you're suggesting is at best distasteful and at worst bordering on harassment.
As I had stated before, I had told the tenants that if there was a medical condition that ruled them out from using feminine products to please provide a doctor's note. Otherwise, each unit would be held 50% responsible for the bill. An update to this is that I have now discovered that there are also baby wipes that were crammed down there as well, and only one unit has a baby. I pretty much consider this case (in terms of whodunit) closed. But now there's even more to the saga:
Upon going to sanitize the basement, it was discovered that the FRESHLY SNAKED PIPES had fistfuls - literally - of baby wipes crammed in the pipe. These were just cleaned out by the plumbers so it is impossible that they were in there again, at least not at that volume. The wipes were photographed and documented. I think I now have my "willful destruction" case, because there is only one tenant with access to the basement, and it's the tenant in question.
Thanks to @Ryan B I did remember that I can now move forward with an eviction based on that, not just the rent issue. However, I do not think that precludes having legal advice, so I respectfully disagree with Nathan's post. I think the comparison of a couple hundred in legal fees vs a couple hundred in plumbing fees is rather myopic. The broader issue, and the case for spending money on legal, is because of the very real potential retaliation/discrimination issue with this tenant. I think spending a couple hundred dollars on sound legal advice in this case isn't just prudent, but is in essence as close to an insurance policy as you can get.
I'm not a lawyer, but in my business role I negotiate contracts for physician groups. I also investigate and defend physicians and medical groups against unfair insurance company practices in mediation. I guess you could call me an "expert witness" of sorts. Regardless, I have a healthy understanding for when and up to what point you can manage something on your own before you should turn to other resources, and I think I'm at that point with this issue.