The suction and return lines that carry water between your pool and the equipment pad run underground, usually beneath a concrete deck. When a fitting or a length of pipe fails, the water escapes where you cannot see it, and the only clue is a water line that keeps dropping.

A detection specialist pressure-tests each line in isolation and uses acoustic listening gear to trace the escaping water to a single point. That is what lets a repair crew open up one small section of deck instead of guessing across the whole run.

A pool that drops faster with the pump running (a pressure-side return leak) or faster with it off (a suction-side leak), soggy spots in the yard, or air in the pump basket.

Confirm it is a real leak before you call anyone. Rule out evaporation with the free water-loss test or the bucket test. If it is more than evaporation, a detection pro pinpoints the exact spot so any repair stays small.