The amount of water usage differ from household to household so it wouldn't make sense to charge a standard fee.

As of the first week of May 2023, 5,093,000 of households were behind on rent.

You need to use household income. 

Median household incomes don’t align.  

Check out David Stone's application criteria somewhere in this link as it have stuff you want to adopt (or copy) for yours:https://www.biggerpockets.com/forums/52/topics/724...I usually qualify 3x income for combined household income.

Will your wife be able to support the household without your income?

A lot of used hotel furniture is better looking and better built than most new, reasonably priced, household furnishings.

It's more common to require the total household income to meet the income requirement.

All I do is co-living households, and my wife does short-term rentals.

Paul area.The magazine notes that Huntsville’s median annual salary is above the national average, but residents spend about 19.62% of their median annual household incomes on the cost of living.According to U.S.