Cash flow is not the primary motive in this case, but I look for it to provide a buffer for unforeseen events, rent compression, etc.

Downside is it makes it kind of a seller's market so cap rates are compressed some!

but, food for thought - cash flow has been compressed because of where the market is.  

Specifically trying to find the following metrics for the Dallas Fort-Worth area, but any general industry metrics would be a good start:- Co-warehousing expense ratios - Current cap rates for this type of facility AND- Projected growth or compression of cap rates

You can probably have a plumber come out for compression test without having water turned on, still requiring written seller permission, but I don't think typical home inspectors will do that, and prepare to be responsible if any damage done.   

Typically, the high end can compress quite a bit while the low end simply does not have that much room.

Cap rates in Broward county have not been compressed as much as they have been in Miami.

I currently have rentals in Salt Lake City where the CAP RATES are very compressed (~4.5%).

If you have individual cut-off valves to the cold and hot water side under the sink with 3/8 screw-on compression lines, I would: get a spare connection line from Lowes/HD, turn off the valve, unscrew the line from the cut-off, screw on the new line and point it into a bucket and turn the valve back on.

As the public data and availability of data becomes easier, I definitely understand the compression of that business model.