Even in the US, private wells and septic systems are common outside of cities and smaller towns. My parents have their own in a village of around 3000 people,

Even in the US, private wells and septic systems are common outside of cities and smaller towns. My parents have their own in a village of around 3000 people, but they're on the border and people closer to the center are on a municipal system. The levels of government, in order from largest to smallest, are roughly as follows: Federal State County Municipality (city, township, or unincorporated) (names for these vary by state). If you live in an unincorporated area (basically, rural space between cities or suburbs) or a town, you will need your own well and septic system.