The average Philly 16ft row house roof has a slope to the back of the house where it drains down a downspout into a drain which catches both downspout water and all water from the backyard which slopes into the drain and then into the main sewer plumbing.  

Roofs need extra layering material (to protect from all the ice and snow), many plumbing systems use cast-iron drains (which are tougher to tie into than PVC), many houses actually have wells for water (ours used to, and now we have to abandon it properly), electrical codes are different (this should actually help us), etc.

I feel like I am throwing my money down the drain. should I try to foreclose;and get some money

More time consuming (and therefore expensive) but still doable.By the way, in a house that has been empty with the water off for 2 years there are going to be muliple leaks at every faucet, toilet and drain.

Rental property is a money drain, unable to sell even at discount, banks say no to loan mod.

If the building still has knob-n-tube, you may have troubles with insurance.Similarly the plumbing could contain lead or galvanized pipe - both of which you will want to budget it replace - on the supply side and galvanized, cast iron or clay on the drain.  

I am considering taking an extra $10,000 of equity out of my home so I do not have to drain my savings to make the duplex purchase.

Replace exterior doors.Plumbing - replace galvanized water & drain lines with PEX & PVC.  

For example, does the stove work well, is the plumbing fully operational, do all sinks, toilets, and laundry drain properly.

Turned out it was a broken drain handle