Wastewater and wells in MHPs and Tiny Home Communities

[Ed O.]

I'm curious to hear how these are set up in newer developments where city water and sewer are too far away. Sewers to me are a foreign concept as I've been fortunate to always be on city water and sewer. 

What would a new, rural setup look like for say, 50 to 100 units. Is there a rough and dirty rule for sharing wells and using a common septic for multiple dwellings to ease up on costs and make things for efficient?

Thanks in advance!