My Septic Tank Overflows From Too Much Rainwater During The Colder Months. I Fear There Is A Rock Bed Under The Lines And They Become Saturated Too Easily .I Hear This Is Common For North AL. How Do I Determine This? Have You Heard Of Seepage Pits?

Same problem here in East TX.  We pumped the system and the tank filled from back flow before the pumper left the location.  He suggested a remedy of installing a small tank with a pressure pump on the outlet line.  I called a service company that did this.  The cost around $2k.  An aerobic system, $5.5k.  No guarentees that the pressure system would work. Problem now, the ground is so wet the installers can't install a complete new system.  We had this problem about 5 years ago with excessive rain but there was an overflow that relieved the tank.  And a smelly mess along with it.as you can imagine.  We capped that and thought all was ok if we kept the tank pumped., not so, Best relief but expensive is an aerobic system.  It is the only kind we can install in this county.