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

https://weekly-wiki.win/index.php/Trustworthy_Sewage-disposal_Tank_Emptying_and_Setup:_Smart,_Cost-Saving_Techniques

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