Went back today for the inspection and poked around some more while the inspector.. inspected things. I really thought I took pictures of the inlet this time, but I'm not sure what happened there. Regardless, I think I've discovered the water source. This house (and pond) are located below the cul de sac at the end of the neighborhood. I walked up to the cul de sac and found three very large, very deep storm drains that connect and then dump into a drain that looks very much like it runs to the inlet of the pond. I think the pond is nothing more than the neighborhood sediment basin.
I'm not sure if this is a good thing, it doesn't seem like it would be a good thing.
