spdrun, I haven’t been to Europe. Are there a lot of septic users outside of cities?

Why do you think property taxes are lower in the EU?

Septic tanks: depends on country and location.
http://www.survivefrance.com/profiles/blogs/fosse-septiques-septic-tanks-in-france

Lower property taxes: because the primary tax burdens are income tax and VAT, and municipalities receive more of that money back from the central government. As it should be in my book.