You prob. are, but are you using a septic tank treatment every 6 months.  We had a neighbor who built a new house.  Old one never had a septic, just an open drain for everything into the feed lot.  Anyway, nobody told him to use a treatment.  After a few years his tank was full.  Needed to be pumped.  He said the plumber never told him he needed treatment.  Not a dumb person.  All the 3 brothers have 4 year college degrees and came back and are good farmers.