Make the QWR a zeroed in well aimed marksman's shot, not a spray-and-pray.

The good thing is that when PB leaks occur, they usually (90% of the time from experience) start as a small spray that tenants will notice.

I haven't been able to resolve our issues here either, but we on occasion once a tenant leaves is to pull off the register, scrape the texture, spray a 10-1 ratio bleach and water on the affected area, let dry and get a can of spray texture and then touch-up paint. 

Twice a year, I go by and house out the condenser coil with a water hose with a good spray nozzle on it, spray some ant spray around the outside of the electrical compartment, and make sure they are keeping the filters changed.  

I have had one issue with a cat spraying, but the tenant's deposit paid for new carpet so it did cause me work but I got the free carpet out of it.  

This is more for multifamily properties: if you ever have an issue where one unit is complaining about bugs, don't just send the exterminator to that unit, but also send them to every unit surrounding that unit (or just spray the whole building).

I had one that was spraying out of the fill valve. the spray was hitting the tank top and running down the back. you can only get parts by special order, but they are free.

@Frances S. so just decide whether you want to go spray them or they should and let them know.

I am in the middle of spraying the house so I will catch the next meeting.

I am sound proofing the ceiling by adding closed cell spray foam insulation not only to the walls, but to the ceiling as well.