No) has diabolical plans to take over the internet spreading this BP addiction in every household!

Please don't tell us you relied on the listing agent, :) The state, cities and large water districts have all kinds of info available to understand and project CA household water use.I wouldn't have used less than $150 per unit.  

We are primarily interested in Buy-and-Hold investing and the areas we were looking in have an estimated 37% percentage of households that rent, meaning that there is a pretty heavy supply of renters.

Fair market rent in the area is $1200 but you can easily demand more based on nearby schools, neighborhood amenities, etc.We want to move into a new house in the next couple of months for a pending household size increase.

Is there a "best" book or comprehensive resource anyone cares to recommend that really covers this stuff in a easily digestible way?

If you know what city and/or county the prospective tenants live in, you can search by the individual municipal and county courts ( almost all OH courts have they records online), but I not aware of a free comprehensive site for Ohio.

While most people like units, I dislike households paying low rents in urban areas of CA.

For a more comprehensive answer, you should immediately contact a local attorney licensed to practice in your state.

GDP, household income, unemployment rates etc?

And owner occupants, for rent to own, who did NOT pass prequalification that you can qualify in the next 12-36 months, have a strong combined household income, and are looking to purchase in the $150k+ range.