If you are buying a home in the County, I strongly suggest that you have the septic system (tank, distribution box, etc.) inspected by a qualified company.  Just because everything is neatly tucked away underground, and seems to be working fine, that does not mean that, in fact, all is well.

Septic tanks can crack.

Connections to/from the distribution box can crack.

Distribution lines can be crushed or crack.

Regardless of whether the buyer or the seller is paying for it, as a buyer, it is worth having the septic system thoroughly evaluated when purchasing a home on a septic system.