A vanishing edge pool is inspected by controlling the autofill, marking the main pool and catch basin separately, testing with the edge system off, testing with the edge running, and inspecting the basin, weir wall, waterproofing, plumbing, and valves as separate components. Wind and splash-out must be ruled out before any finding is called a leak.
Why Vanishing Edge Pools Are Different
Water leaves the main pool by design, flows over the edge, enters a catch basin or trough, and is pumped back to the pool. Some systems also include a surge or balance tank. Many have autofills in the pool, the basin, or both.
The main pool can drop while the basin holds. The basin can drop while the main pool holds. An active autofill can hide either loss completely. A technician has to slow the system down and test one section at a time.
What Needs to Be Inspected and Separated
Test in Two Operating Modes
Both modes are required. Testing only one gives an incomplete picture.
Critical Control Steps Before Any Testing
Skipping these steps produces unreliable results.
First -- turn off or measure the autofill. If the autofill is feeding water into the pool or basin during the test, the water-level tracking is meaningless. Either shut it off or document its run time accurately.
Second -- mark the main pool and basin as separate measurements. Tracking only one gives no information about which vessel is losing water.
Third -- document wind and weather conditions. Wind-driven splash-out across a vanishing edge can look exactly like a plumbing leak. Calm conditions make testing more reliable.
Common Mistakes
Jeff David's Perspective
Vanishing edge pools are where a lot of well-intentioned technicians give the wrong answer. They find a crack on the edge wall, call it the leak, recommend waterproofing, and the pool keeps losing water because the actual problem was the autofill running through a slow check valve leak into the basin. The repair was done, but the wrong component was repaired.
These pools require a systems mindset. You are not diagnosing a pool. You are diagnosing a hydraulic circuit with multiple vessels, multiple pumps, and multiple possible failure points. The diagnosis has to match that complexity -- or the repair recommendation will not hold up.
-- Jeff David, Founder | Leak Business Academy, LLC | Leak and Subsurface Locators, LLC
Test Each Vessel and Each Mode Separately
A vanishing edge pool is inspected as a connected system -- not a single pool. Control the autofill, mark the main pool and basin separately, test with the edge off and on, inspect the basin and weir wall, check the waterproofing, and pressure test edge plumbing when symptoms point to a line. Separate splash from leakage. Separate basin loss from main pool loss. Separate static loss from operating loss.
Learn Vanishing Edge and Complex Pool Diagnostics
Leak Business Academy, LLC teaches the H.U.N.T.E.R. Method as a systems-level diagnostic process -- including multi-vessel pools, connected plumbing, and operating-mode testing.