My wife and I recently purchased a 6 year old home. The home has well and septic systems and since we've both been city dwellers up to now, we are newbies when it comes to operation/maintenance of septic and well systems. I had the well water tested prior to purchase, and was told there were no organic/inorganic contaminants, but was recommended to install a water softener. As part of the home inspection, I had the septic system checked by a local septic professional that was recommended to me by several local building professionals. When I mentioned I planned to install a softener, he recommended me to NOT hook up the softener waste line to the septic system. He was not concerned about too much water from the softner or damage to the bacteria, rather he was concerned about damage to the concrete septic tank from the salt. He says he has seen numerous concrete tanks eaten away at the outlets due to the salt from the softener.

Is this truely a concern? If so, what can be done about it? His suggestion was to put in a mini-septic system. What is meant by this and what is the rough cost to do something like that?