The Wet Spot
Wet, maybe very green, spot in the yard?
It is a pretty sure bet an unexplained wet spot out in the yard/property is a water pipe or drain problem.
There have probably been higher than normal water bills leading up to a spot/area such as this.
For some reason, these spots are good at occurring where folks don't go into the yard/property very much.
It is a pretty sure sign a plumber is needed.
Ironically, this one was found outside a home which had a small, bet very smelly fire. The spot kept slowly getting wetter with any water being used in the home, so it was most likey a water pipe instead of a drain pipe. A drain pipe would only leak when water water turned on.