We have a septic tank serving our house in France. This legislation is (dare I say it) Europe wide legislation, so we too have to to follow it
Fortunately we had to replace our previous system when we installed extra bedrooms in the house in 2008 as the size of tank is dictated by the bedroom numbers. Because the land does not drain well we had to have a huge hole dug in the front garden and then filled , in layers with three different sizes of gravel. The water has to be pumped up to the front garden and we have to keep the pump on 24/7, even when we are not there.
Apart from that it has been no trouble at all. We buy boxes of sachets with an enzyme accelerator, which we flush through when we arrive and leave, although that is not necessary, just a belt and braces action and, as the French implemented the new system some years ago, we have since had two official inspections from an organisation wonderfully acronymed SPANC and passed both with full colours. Our system will only need pumping out every 15 years.