Here’s another example of why it’s so important to located and open the D-Box during a septic inspection. In this case I inspected a 30 year old stone and pipe system in Pittsfield NH. The treatment tank was in good condition as was the EDA. When I located the D-Box and opened it up I found it to be mostly deteriorated. The baffle inside was completely gone, there was about 3-4 inches of sludge in the bottom (which will migrate out into the EDA) and the sides were cracked.
Replacing a deteriorated D-Box is not that difficult and by doing so it may save the EDA.