As unfortunate as this answer may be, if your system is backing up and overflowing, pumping the tank will only temporarily relieve the symptoms of septic failure (the back up) but it will not fix the problem. But don’t panic.
Here’s what to do:
First make sure it is your septic system that is backed up and not just your main line. The way to do this is to open your septic tank and look inside. If it is all the way to the top over the septic inlet and maybe even coming out the lid then the problem is the septic leaching system.
If you can see either the inlet or the outlet the problem is in the line. First check the inlet. Many times toilet paper has built up in front of the septic inlet and you can take a shovel and push the build up aside and the main line will clear itself.