1/3 of septic tank under the living room extension

Is it bad if 1/3 of septic tank is under the living room extension? Our house is facing east with main door also facing east. The septic tank is located on the SE corner of the lot. How to cure this if it is bad? My husband birthdate is 19 March 1956, my birthdate is 04 Dec 1954, my mother's bd is june 05, 1931, my eldest daughter is 25 March 1986, son is 18 June 1992 and youngest daughter is 28 April 1997. Thanks in advance for replying to my question