Trouble Comes in Threes

Over the last few days, a lot of things have started going wrong in my house.  It started when I came home from work yesterday to find my fridge leaking.  The leakage looked like it was coming from a water filter cartridge in my fridge, so I've had to shell out on a replacement today to see whether that solves the problem - let's hope so (it wasn't cheap).  And then I got woken up in the early hours by the loud sound of scratching in the wall behind my bed headboard.  That freaked me out - definitely sounded like I've got some kind of pest problem, like mice or rats or worse (a raccoon?).  That's the first time I've heard anything like that (minus the wasp nest from a while ago) - maybe because I sleep with earplugs in so I might have missed any earlier noises - but that is definitely something I need to let my landlord know if it happens again.  I did a thorough check around my house today, and at least I don't see any evidence of droppings or anything.  And then when I was outside earlier today cleaning my car, I heard the sound of water and then was hit by this horrific smell - I suspect it was my septic tank.  It stopped after a little while, but I've got no idea how septic tanks work and whether that is normal.  I maybe need to landlord know about that if I smell it again, in case the tank needs emptying or something is wrong with the system.  Just thinking about that smell again makes me gag.  All these things just confirm my belief that if I ever buy my own place, it has to be new or newly built - I don't have the capacity to deal with these kind of issues on my own.