If anyone could provide me a link to the FHA guidelines, I would certainly appreciate it.By the way, here's probably the best article I've found on the subject:https://www.mass.gov/info-details/arsenic-in-private-well-water-faqs#:~:text=Unless%20your%20arsenic%20level%20is,not%20evaporate%20into%20the%20air.One notable quote from it:"Unless your arsenic level is over 500 ppb, showering, bathing and other household uses are safe.

The total assistance amount available will depend on household need.To qualify, applicants must:Rent housing in the city of Sacramento or an unincorporated area of the county.Have experienced a loss or reduction in wages due to COVID-19.Owe back rent or have an inability to remain current on rent.Have a current household income that does not exceed 50% of Area Median Income (AMI).Not live in public housing or receive ongoing rental assistance.For more details on the program, visit www.shra.org/sera.

“Many renter households across the country could find themselves with no place to live and no means to repay missed payments.”  

I am trying to determine our real cost of having one extra person live in our household.  

It might be easier to look for a roommate situation in an already existing roommate household. 

Be a Betelgeuse...There are elements of their household that seem determined to stay no matter what. 

@Elijah Householder My vote is house hack all the way.

While population growth is a good metric to evaluate, household formation might be even better.  

Therefore the young generation began staying at home in the basement with mom & pop for longer thereby creating a lot of pent up household formation. 

Some indicators you can look art are- job growth, employers in area, median household income, rent rates, crime in the area, etc.