I would absolutely use the pipes as a hit against the property when negotiating to try and justify a lower purchase price, but I would wait until there was a sign of failure to replace anything. 

The single property is a single point of failure.

The important thing that you are going to have to realize is that your failure to notice that the rent wasn't coming in contributed greatly to this situation.

Answer:  Put a for Lease sign in their window.....and yes it's in their lease that I can do that for failure to pay rent.

Some common disputes I see are concerning the landlord failing to do his or her duties under the lease (e.g. make repairs); slip and falls by a tenant or a guest of the tenant; injuries caused by landlord's failure to properly exercise his or her duties; environmental issues at the property (typically commercial, e.g. alleged that an underground oil tank started leaking causing damage to business); disputes over the security deposit; illegal clauses in a lease; failure to reimburse the tenant for a repair he or she made; Entering a tenant's property illegally; failing to disclose environmental issues such as lead paint; or trying to evict the tenant illegally.

Your failure to mention these caps leads me to believe you either don't observe them or don't know what you're doing.

If they can't give you some analysis in this regard, it could indicate they are not using resources to really track and understand leads and lead failures. 

I've found having clear flowcharts and processes for the business creates a high level of success and less failures in the future.

Heating, air conditioning, hot tubs, major appliance failure, septic issues, etc.  

If not, then you're setting yourself up for failure if you can't MTR in time.