F’ing Septic Tanks

Sounds like your drain field is plugging off, so things can't run down hill.

There is a catch point on the exit of septic tanks where they use a rubber coupler to connect the tank out line to the drain field line. Takes like a 75 foot electric snake to come up from the down below clean out at the drain field to reach the rubber coupler at the tank and clean it out so ut can flow properly.

Also most septic tanks have 2 stand pipes for servicing, that should be capped above grade. Some folks will cut and cap them below grade so they can mow right over them.

If not sealed properly this can create a funneling effect and can run water directly into your septic tank every time it rains. Not a good situation.