Thank you everybody,I used  http://www.tlv.com/global/US/calculator/water-flow-rate-through-piping.html.do calculation,It shows the velocity in the pipe is 2.43 ft/s. standard faucet today will cause around 0.3 ft/s in a ¾ inch pipe.

Especially since radon is known to cause lung cancer.

Buyers only have the unit inspected which is great but if the building is falling apart around them they're going to be exposed to special assessments and potentially damage to their unit (roof and exterior leaks).

Should the property become further damaged/vandalized After you have a contract, then perhaps, but not otherwise.

There are all kinds of disorders that can cause weight gain.

Like foundation work, mold damage, water damage and things like that.

Some good answers: Moved out of town, inherited a property, massive ____ damage, tenants ran out on me, etc. 

And yes, it causes a little more work for the CPA... but I am sure he charges me for it anyway.  

you have some homework if this is not self-evident.(3) should cause you to shutter - - one or two persons can not maintain 75 units (even all SFR) and  it's worse if its 75 doors of MFU. 

first some background:I'm buy a property with two duplex, one of them has structural damage and I am going to tear it down.