A: There are many possible causes. When you call us, we’ll ask a few key questions to help diagnose:

• When was the last time you had your tank pumped? Too much time between services can lead to issues.

• Is there a filter installed on your system? Filters help avoid hair, grit and debris from clogging the drain field.

• Where is the backup occurring (e.g., upstairs toilet, outside drain field seepage)? The location helps determine the likely problem.

• Is just one area of the house backing up or the whole house.