I've had my plumbing backwashed twice and the plumber reports it's because the pipes in our condos are old and corroded inside. That because my unit is the end one in the complex (we don't have individual meters add the complex pays the water bill) all of the corrosion that's breaking loose from the other units is ending up at my unit because it's at the end.. Is that possible?

Yes, I could see that. Is this hot and cold? Could be a deteriorating dip tube too but I hope the plumber would realize that too.Just unscrew the aerators and leave them off. May have a shower head issue but can backwash. How about a whole house filter?

Install your own whole house filter GE 1 in. High Flow Clear WH System-GXWH40L at The Home Depot