One expensive septic system repair has to do with the distribution box. Back in 2015 it cost me $2k to have that fixed on a house I was selling. That was a low end price for the work.
Here’s info on the septic system d-box:
“A conventional septic system is composed of the septic
tank and the drain field. The drain field is where the last stage of wastewater treatment system takes place. It is the area of effluent purification and distribution. An essential part of the drain field is the distribution box. If you think about it, its name gives it away. It is a structure that connects the effluent pipeline from your septic
tank to the lateral line, seepage pit, or galley networks.
The distribution box or d-box regulates the dispersion of the treated effluent. It is a must for the d-box to remain properly installed. If it’s tilted or clogged, it will only distribute the effluent on one part of the drain field. it will eventually result to the bursting out or overloading of the effluent onto the surface of the yard. Like the rest of the septic system, you should have the distribution box regularly inspected because. It is very prone to clogging and saturation. If you knew that the drain field has been flooded before, then you should get ready for a malfunctioning system pretty soon. To prevent that, talk to your septic expert immediately.”
What is a septic system distribution box?