Open lids carefully, check inlet and outlet baffles and tees, document fractures or rust

https://research-wiki.win/index.php/Reliable_Septic_System_Emptying_and_Setup:_Smart,_Cost-Saving_Methods

Open covers carefully, check inlet and outlet baffles and tees, file fractures or deterioration, and repair seals to stop groundwater invasion and exfiltration that can overload the drainfield.