| Just a dumb electrician here, so just guessing, I am thinking it is intended to be a dry well to drain the pool pump/filter. To confirm it is related to your city water, perhaps you can shut off the water at the main valve, for a day if possible, to see if the well still fills up.
While your city water is on, does the meter still run when you know you have every sink, spigot, and hose shut off? Observing this will help confirm water usage that is running up the bill. I know some utilities have the meter inside, while some have the meter out in the yard or at the street. With the meter inside it is easy to check usage, and any leak will be noticeable.
I can imagine a meter in the ground out at the street is much more difficult to check, and there can be a leak in the underground piping that is not noticeable, running up the bill , and allowing water into the ground, and could contribute to the water rising in the "well".
Real mystery you have. Perhaps if you copy your question to the plumbing forum, reword the heading a bit to get someones attention that your question is not just about pool equipment , you may get a better answer. |