The pipe is a bout 1.5 inches in diameter . it might not look like its a size of a dime from the bottom nut if you go from the top i could tell that the damage has made it through the ceiling.Ive spoken to a couple people and they said its probably from the rubber surrounding the vent pipe.  

Here it is with Sch. 40 PVC for comparison: same internal diameter, very different thickness.

A local TV company dumped a 6' diameter cable spool on one of my lots.

Or, get the fixed kind that are like 4"-6" diameter, like some hotels have.Is there an outside hose bibb? 

15.5" diameter hole with an 18" diameter lip.

Also keep in mind, there are certain requirements in juridictions for pipe diameter as a function of both distance run, and number of pipes feeding the primary line.  

I think I had to span from one pier to the next and I bolted the assembly together with 3/8" diameter carriage bolts.

I recently hiked across the wilderness portion of the land and found two aged stone circle rings about 6 foot in diameter.

I can offer advice regarding the water well if you have any details about it (diameter, material, age, and detail about the pump installed).

The City is trying to get the diameter of the service upgraded, plus a long term goal of getting rid of lead pipe.