Yes -- trace gas passes through soil and concrete and surfaces at the exact point of an underground pipe break. It's the most precise non-invasive method for locating pool pipe leaks without tearing up large sections of deck.
Most pool deck leaks from underground plumbing leave no visible sign at the surface -- no wet spot, no crack, no indication of where the water is going. The pipe runs under the concrete and the break could be anywhere along its path. Before trace gas was used in pool leak detection, finding that break meant cutting exploratory trenches along the pipe run and looking for it. Trace gas changed that completely.
Waiting for trace gas to passively migrate up through a concrete pool deck is too slow for practical field work. Instead, the technician drills small strategic holes in the slab at intervals along the pipe path. These controlled release points give the gas a direct path to the surface sensor. The technician checks each hole with the sniffer and identifies where the signal is strongest.
The hydrogen molecule is the smallest in existence, which means it also escapes readily through natural cracks, expansion joints, and any existing penetrations in the slab. The technician checks these first before drilling. Drilling is only done with the client's awareness and is part of a controlled, methodical process -- not exploratory damage to the deck.
LSL uses both the 5% hydrogen / 95% nitrogen blend and helium depending on the situation. Both are non-toxic and non-flammable at the concentrations used in leak detection.
Once trace gas has been introduced and allowed time to migrate -- typically 5–15 minutes depending on depth and soil type -- the technician begins a systematic surface scan. A handheld hydrogen sensor with a wand tip is moved slowly along the deck above the pipe's known path. The sensor produces an audible tone that increases in frequency and pitch as hydrogen concentration rises.
Far from the break, background signal is minimal -- hydrogen disperses quickly once at the surface. Directly above the break, signal is strongest. The technician moves back and forth to identify the peak, confirms the location from multiple directions, and marks it. That mark is where the concrete is cut.
The most common residential pool deck configuration in South Florida. Trace gas migrates through standard slab thickness reliably within 10–15 minutes of introduction. Signal is clear and precise. This is the ideal scenario for trace gas testing.
Pavers with a sand bed underneath are actually easier for trace gas than poured concrete -- the sand is highly permeable and the gaps between pavers allow gas to escape readily. Trace gas surfaces quickly and signal is easy to read. Very common in South Florida pool decks.
Decks over 6 inches thick, or concrete with a secondary topping slab poured on top, require more time for gas migration. The technician allows additional dwell time before scanning. Signal is still detectable but may be slightly more diffuse. Depth of the pipe below the deck is also factored in.
When pool plumbing runs under a structure -- a covered lanai, equipment room, or portion of the home -- trace gas still works if access to the structure interior is available for scanning. In some cases, limited access affects precision, and the technician documents the constraints as part of the report.
The practical outcome of trace gas work combined with acoustic listening is a narrowed excavation area rather than exploratory trenching. Without location information, a repair crew follows the pipe path and opens sections until the break appears. With the break zone identified by acoustic and trace gas work together, the opening can be targeted to a much smaller section. Less concrete removed means lower restoration costs and less disruption.
Learn more about your pool's water loss pattern and whether underground plumbing could be involved.
Leak and Subsurface Locators uses trace gas testing on every underground pipe investigation. Call Sandra before the repair crew starts digging.
Typically 5–20 minutes, depending on pipe depth and soil composition. Shallow pipes in sandy soil (common in South Florida) surface quickly. Deeper pipes or clay-heavy soil may require additional dwell time. An experienced technician judges based on the site conditions and the strength of the initial signal during the first scan pass.
Trace gas is introduced under pressure that's maintained in the line during the test -- so even a very small crack that barely loses pressure during air testing will allow gas to escape underground. The sensor is sensitive enough to detect small quantities of hydrogen. However, a pinhole that's nearly sealed may require longer dwell time before a reliable surface signal develops.
Wet soil and water saturation can slow hydrogen migration because water partially fills the soil pore spaces that gas would otherwise travel through. Testing after heavy rain or in waterlogged ground may produce weaker or more diffuse surface signals. In South Florida, where afternoon rain is common, scheduling trace gas testing in the morning after a dry overnight period produces the best results.
Yes. If pool plumbing runs beyond the pool deck -- under a driveway, through landscaping, or toward the street -- trace gas follows the pipe path wherever it goes. The surface scan follows the pipe route as mapped by the pipe locator. As long as there's surface access above the pipe path, trace gas can identify where along that path the break is located.