Dirty water (sewer) leak into house is much tougher to deal than clean water leak. I have to bite the bullet. We probably had 4 septic tank pumpings last year and two this year already.
My guess is that tree roots grow too much in the drain field so caustic treatment was not that helpful. I may be able to fight with city to allow me to have a new drain field with old tank. City won't allow new tank/drain field.