If your water bill is as high as your neighbor's, and they have 5 people living in their house and you have 2, and they water their lawn 2x per day while you do yours 1x every three days, and you pride yourself on your tiny green footprint, and you call the city water department, they'll tell you how to do a simple water leakage test (or you can pay them $24 to have them do it). You turn off all the water sources in your house, and then look at the meter to see if the little blue thing is spinning, and if it is you have water running or leaking somewhere. Assuming everything is turned off, if you're brilliant, you'll turn off the valve to pool's auto-fill, and then if the blue thing stops spinning, you'll know where the leak is. Please do not keep pounding your head against the wall lamenting how much water and money you've wasted for months or even years. Instead, pat yourself on the back for your brilliant deductive catch of the key valve resulting in your solving the case, which only someone with Monk's deductive powers could do.