My house was converted to municipal water years ago (before we moved
in). In the back yard were two pipe openings that were remnants of
the earlier septic system. We were told they were for the drywell.
When having a tree removed, the stump grinding machine caused a sink
hole to occur. It is around eighteen inches deep and about three feet
in diameter but it was about twelve feet from the nearest drywell
opening. Obvioulsly we will need to fill it in but I'm interested in
any thoughts on why this happened and the best way to deal with this.