1 tank types from Snyder Industries.
Plastic Tank
Snyder makes rotomolded poly tanks that are approved in many states for septic use. The 1,000-gallon model is a one-piece tank, which some installers prefer over two-piece designs for the simpler watertight seal. It is lightweight and holds up well underground, though you need to be careful backfilling around it so it does not shift.
$700 - $1,100