I think it depends on the country to a large degree. In industrialized nations, regulations are much more complex and surface- and ground-water protections tend to be more stringent. In more agricultural locales, the issue becomes one of not creating a nuisance or hazard with one’s waste, more than complying with the letter of a regulation. But you still need some means of managing waste - septic tanks are common because they are effective, but they depend on an abundant supply of water. If there is not water to flush, there will not be a septic tank.