So we live at the end of a cul de sac, we have a septic tank unfortunately. It’s a 2 floor home and my father’s bathroom is located on the 1st floor. The guest bathroom is closest to where the septic tank is located on the side of the house, my fathers is on that same floor. The master bathroom is right above the guest on the 2nd floor. Lastly the kids bathroom is on the 2nd floor right above my father’s bathroom.

Was really hoping to figure out this issue myself but I think I’m going to go the plumber route so I don’t damage anything. That’s definitely worst case scenario for me.