It could be the water supply line dripping on to the floor.

Some things to be mindful of are the added costs of having to facilitate delivery and acceptance of the windows if you are purchasing them yourself rather than go through a contractor who both supplies and installs the windows.

Or at a local real estate meet-up is another great option.3) IMO (duplex, triplex, quadplex) are best, butttt in some areas supply is limited.

Our plumber re-plumbs entire houses for much less than that, and if it's a simple leak you can find, you could be done for a few bucks.The 80's were the era of pinhole copper, so there's always a chance that your supply lines are shot when buying a house from that time period, but it could be something minor too.

Higher than inflation appreciation will occur where demand outstrips significantly supply. 

While I don't supply paper towels, each of the three bathrooms is stocked with three rolls of toilet paper.

Phoenix, AZ has been a great market for the past 10 years, but not so much in the past two years, as supply has really started to inhibit price and rent growth.

They need to connect with one anther and to the unit supplying them.  

My advise is to start with single family or a small multi-family ground up project first but this market environment is truthfully not the time to be completing any ground up projects unless you are self performing the construction which it doesn't appear you are in a position to do.There was a recent Philadelphia  forum chain started by someone else who was contemplating ground up in a similar fashion to what you are proposing and I cautioned they would be better off buying something that was newly built and believe after conducting their own diligence realized it was too cost prohibitive at this time to build with 3rd party GC's in Philadelphia when also accounting for the interest rate environment and cost to build.

BULLYING is never OK, not in any shape, form, or fashion.