Step One: Establish the Water-Loss Pattern
The diagnostic process starts with the reported water loss, pump schedule, attached spa, water features, autofill operation, recent repairs, and visible equipment behavior. These observations establish which tests belong first.
Pump-on and pump-off patterns can suggest a return-side or suction-side problem, while a consistent stopping level may point toward a fitting or shell penetration. These patterns are clues and do not prove the source by themselves.
Step Two: Dye Test the Pool Shell and Fittings
With circulation controlled and the water calm, dye testing checks skimmer throats, return fittings, pool lights, cracks, tile-line separations, and other shell penetrations. Directional dye movement identifies an active water path.
A dye test is useful only at the point being examined. When visible areas do not explain the measured loss, the buried plumbing moves higher on the test list.
Step Three: Isolate and Pressure Test the Plumbing
Returns, skimmers, drains, cleaner lines, spa circuits, and water features are isolated whenever the plumbing layout permits. Controlled test pressure shows which circuit holds and which circuit produces a repeatable loss.
Valves, check valves, inaccessible fittings, and shared plumbing can affect isolation. Any limitation is documented so the test result is not presented with more certainty than the system allows.
Step Four: Narrow the Underground Location
After a line fails pressure testing, pipe tracing establishes its likely route and acoustic equipment checks for a repeatable underground response. This sequence keeps listening focused on a confirmed leaking circuit.
The marked area represents the evidence-supported access zone. Deep burial, saturated soil, hidden reroutes, and multiple leaks can affect sound, which is why the location and its limitations are recorded before excavation.
Step Five: Document the Finding Before Repair
The final finding connects the observed symptom, test result, pipe route, and suspected access point. Photos and written notes distinguish what was confirmed from what remains uncertain.
Precise diagnosis helps avoid unnecessary deck openings and directs repair toward the supported failure. The repaired line or fitting should be retested before restoration is treated as complete.