Not to pour water on your surveying parade, but I know a lot of civil engineers who are underemployed since subdivision development work ground to a halt several years ago.

If it is permitted then you would need to think about if you can get city water or well water, gas/electric or propane, septic tank or sewage, etc. if you are planning on putting it on an empty piece of land in a neighborhood with houses then I would consider re-sale value and the fact that the neighbors might not like you for it.

I took the position in April of this year because everyone wanted the former treasurer out for mismanagement of funds when we were slapped with an orange sticker from the City of Chicago saying that we had 10 days to pay a $25k water bill.

I'd scope the sewer line and confirm material of water supply.

After I asked my plumber to come to my properties and look for leaks, I came to the conclusion that my quadruplexes have huge water bills (water taxes?)

The Lease needs to be clear in its definition of what you are trying to accomplish here which is that the Tenant pays for all of the operating and maintenance expenses of the property.In addition be sure to include an understanding of who pays for major capital replacements (not just maintenance) such as replacement of the heating and air-conditioning units, water and sewer lines, electrical mains, roofs, glass, etc.

What is the age of the property and it's infrastructure (roof, water heaters etc?)

My advice is not to waste your money on testing clean with bleach water and buy a mildew mold suppressant from hardware store it's a chemical you put in a pump up sprayer keeps mold from coming back if on a painted surface get a fungicide paint additive and repaint area.

The property itself pays off itself after mortgage, taxes, insurance, sewer, and water - and leaves some to reinvest.

It sustained water damage from a broken pipe in the kitchen last winter.