However, a few other key factors to help you filter through:If ceiling is at least 19 feet you can add a 2nd floor and basically double your Sq Ft capacity (course you'll need to add an elevator)What to do about the Parking Lot - this can be for "Boat & RV Storage" or perhaps use the opportunity to expandAccess Points for easy entrance/exit.And the major wildcard is the city Planning & Zoning - is it currently zoned for Self Storage? 

Before signing a contract to buy, check the absolute elevation, and relative elevation.

One way is to elevate the house on stilts like houses build at the ocean. 

What is the layout, i.e. will ADA require an elevator?  

I don't know if I can provide advice that tops anything that those with deep real estate investment experience in the area might be able to provide, but I've been an interested observer of the Bay Area housing market since the tech economy began rebounding in the early aughts.My take is that property value within San Francisco itself will continue to teeter at an elevated rate for the foreseeable future (this is somewhat of a given considering how small the city itself is, and how fierce the demand for property remains).

This elevates costs for everyone, bringing the tenants' business expense onto the income statement of the property.

I am sure you have done some due diligence online but here are some reads on water heaters in Irving. http://westplumbing.net/plano-plumbing-tips/irving...http://westplumbing.net/plano-plumbing-tips/dallas...Notice that the Dallas article says that FVIR heaters do not need to be elevated but not sure if the same applies for Irving or not.

So when the motivated sellers call, have your elevator pitch leaning towards owner financing ready, "What if instead of buying it outright i could put X dollars in your pocket each month without any of the hassle of being a landlord, etc etc."

., roof structures, HVAC systems, elevators, etc.

Are the units near the elevator or garbage shute - things that another owner (or renter) would find bothersome.