I've lived with a septic system for decades. It's really no big deal (oh, beg pardon - "dill"). If properly constructed and of adequate size, it'll handle the household. I have a tank and leach field set up. I occasionally feed it a box of RidX or a bag of yeast (last time I had to have the tank pumped, and that was decades ago, the technician told me that baker's yeast does much the same thing as the commercially-sold "septic tank maintenance" products. It just gets the digestive action going/keeps it going). I don't have a garbage disposal, but I do have a dishwasher, laundry equipment and so forth. It's like anything else: build it right the first time and you won't have regrets later.
Now that I've just reread that last sentence, and realizing that we are talking about Kody and The Klowns, I guess I might have to take that back. Since the septic system is "out of sight, out of mind", THAT'S the area where they are apt to save a few bucks. Well, may I suggest outhouses? And they can beat their laundry on rocks in that swell fishing pond!