Water Supply/Plumbing question

I went out to turn off my water supply to do repairs on my shower,when I discover about 3 inches or so of standing water in my “hole”.

I’ll explain.The water meters are in a below ground (Abt.1 ft.) concrete sided enclosure with a cast iron lid to keep it,I suppose,protected from prying eyes.

You remove the cover,like the meter reader would have to,to get to the valve that controls the supply.I had to bail out that water just to find the valve,down to,and including mud (the bottom of this enclosure is just the earth-the sides being the only concrete piece to the enclosure.)

I checked my neighbor’s supply box (we’re side by side in a townhouse condo setup) and it was dry-nary a drop of moisture.

So,I’m guessing there’s a water leak (must be slow,else I’d think that enclosure would have rapidly filled back up-it didn’t).But where?I haven’t noticed any increase in water usage lately,so hoping it’s something the water company can take care of.

It’s a holiday so I can’t call them until tomorrow,but in the meantime is there anything I can do/say to the water company to help them diagnose what’s happening?Do I have a liabilty here?

Any dopers have any experiences with matters like this?