I am on the Neighborhood Building Owner's Alliance weekly calls, and we had this ADU issue come up.

I had a similr issue a few years ago with a property in Cleveland where my property manager hit the same roadblock.

I appreciate that, and you're right, any back-of-the-envelope calculation suggests that much of the wealth comes from the equity accumulation, even in the earlier stages of the amortization schedule.

Quote from @Noah Wright: We specialize in this specific issue, actually. 

Give fair housing testers the right to secretly record your call, trying to trap in a fair housing issue.

There's a good chance the issue(s) you face has already been discussed and answered.Ask questions in the appropriate forum.

- The current low rent is probably to offset maintenance issues at the property.- Try to raise the rent and the tenant will give you a list of all the maintenance issues they want you to fix. --- They will offer to fix them in exchange for lower rent, but ask yourself, if the tenant has been living there for 25 years, why isn't everything fixed already?

Current status is that the Dept of Health has not yet issued the Septic Permit yet.

The issue is that you cant cold call people in New York 

I find that the best deals on the market are usually newly listed (less than a week on the market) and usually the deals that haven't sold have significant issues with them.What are the reasons that you think homes sit on the market for a long time and how do you navigate the issues to make a deal that works for you?