Welcome to Pond Boss!!

You can dig test holes yourself, but it's a good question as to what you are looking for.

"Ground Water" or the 'water table' are double edged swords. Where water can come in, water can also go out especially when at near full pool or full pool.

Excerpt from Robert Crais' "The Monkey's Raincoat:"
"She took another microscopic bite of her sandwich, then pushed it away. Maybe she absorbed nutrients from her surroundings."