We lived with our septic system for 8 years without any problems.

In May 2011 the main waste line to the septic tank plugged and we determined that the tank needed to be pumped. Since having the tank pumped and once the tank was full of water, we now have a plugged waste line once a week. The plug seems to always be at the entrance to the septic tank.

Now when the line is plugged and toilet is flushed, air is being forced back up the lavatory drain. I don't understand why for 8 years we didn't have any problems at all and the problems didn't start until after the tank was pumped. Please help.