An interesting puzzle. Raises questions about why the definition of affordable is "a listing ... [where] the estimated monthly mortgage payment is no more than 30% of the local county’s median income.".
How did this figure get picked and what does it really mean? In a wealthy district where people are saving a lot of money, obviously they can afford, in the literal sense, interest payments that are higher than that.
Yeah, I never understood the 30% thing. You need to live on what's left over. If "minimum non-housing living costs" are , say, 20k/year, someone who earns 30k can only afford to spend 33% on rent, but someone earning 100k could afford spending 80% of their income on rent (if they chose to do so).
The 30% thing is completely arbitrary and a massive distortion of reality.
Conventional mortgage qualifications are typically 36% DTI. Debt to income ratio is (PITI + all other monthly debt payments) / monthly pre-tax salary. PITI is principal, interest, property taxes, and mortgage insurance.
It is set by the organizations that purchase mortgages from the bank. If the borrowers don't meet these guidelines they won't buy the mortgage and the bank would need to hold it, which they typically don't want to. See FNMA and FHLMC.
How did this figure get picked and what does it really mean? In a wealthy district where people are saving a lot of money, obviously they can afford, in the literal sense, interest payments that are higher than that.