Is it a bad idea to convert this LTR into a STR?

[Stephanie Medina]

I own a LTR in central Houston that I think would be pretty successful as an STR based on the AirDNA data. I also am very interested in purchasing more STRs, and this is a really low risk way to see if I'm up for it (we have a 2.9% interest rate on our mortgage).

My biggest concern is an ongoing plumbing issue we have had. This is a 3 story town home (detached) that shares a private sewage line with 7 other homes. When we lived there up until last year, 1-2x a year there would be a clog that would cause a backup of sewage in the downstairs tub and toilet. The city would come flush the system, and said everyone needs to stop flushing wipes and pouring grease down drains, etc. It persisted despite our best efforts with our neighbors. Once I turned it into a LTR I was determined to solve it, so I had a very reputable plumber camera the line after it happened again. Long story short, he couldn't see anything wrong, but said he would have a lot better idea if he could camera the line during the next clog before it is cleared. He strongly discouraged adding a backwater preventer bc he said he's seen it make things worse. So that has been my "next action step" to wait for a clog to happen again and have him camera it, but it has now been almost 1.5 years with no incidents.

TLDR: There is a chance that the bottom bathroom tub/toilet could fill with sewage during a guest stay, but I am hopeful that the next time it happens will be the last. I just don't know when or if it will happen again.

Would it be a bad idea to move forward with converting my LTR to a STR? If so, and this does happen during a guest stay, how would you handle the situation? Thanks in advance!

[Stephanie Medina]

Update: I decided I will pay a $500-750 or so to do an initial hydro-jetting of the system.  Based on our history of all this, that could last 1-1.5+ years.  Hopefully I can garner enough good reviews by then that a one time sewage incident review does not wipe out my status.  Then based on @Michael Baum's suggestion, I think I will have my cleaner and/or maintenance person do monthly/quarterly maintenance like using using enzyme based cleaners, grease fighting drain treatments and hot water flushing.  ChatGPT gave me a couple of recommendations on that.  If I can recruit some neighbors to also do some of these things, this may put off another incident indefinitely.  I'll be getting several more opinions from other plumbers as well.  

Another thing I was thinking about was this has been by far the longest we've gone without an incident.  It could have been the tenants of the house right next to my property continuing to flush things they should not have despite lots of warnings from the city, and they moved out a little over a year ago.