Most house leaks are found with simple tools: a meter test, a moisture meter, an acoustic listening device and a thermal camera. Occasionally, a leak is too small, too deep or too quiet for those tools to find. That is where helium or another tracer gas comes in.
In this method, the pipe is drained, filled with a mixture containing helium or hydrogen and pressurized. The gas escapes at the leak, rises through the structure, and a sensitive handheld sniffer picks it up at the surface. This guide covers how it works and where it fits. For the basic approach, start with leak detection.
Method.
How tracer gas leak detection works.
Isolate and drain the line.
The section of pipe under test is cut off from the supply and emptied of water.
.Fill with tracer gas.
A safe, non-toxic mixture of helium, or hydrogen mixed with nitrogen, is pumped into the pipe at low pressure.
.Scan the surface.
The technician passes a sniffer over floors, walls and ceilings and watches the reading. A peak shows where gas is escaping.
.Confirm and mark.
The spot is checked a second time. Repair then targets the marked area.
.
Helium is lighter than air and the molecules are tiny, so it escapes through very small openings and rises. That is why it finds pinholes that water cannot reveal by sound. It is not a flammable gas, and it is the same gas used in balloons, though the working mixture and equipment are specialized.
Comparison.
Tracer gas compared with other methods.
| Method | Best at | Limits |
|---|---|---|
| Meter test. | Telling you whether a leak exists. | Does not locate it. |
| Acoustic listening. | Pressurized leaks that make noise. | Weak on small or quiet leaks, noisy surroundings. |
| Thermal camera. | Hot water leaks and wet insulation. | Needs a temperature difference, shows areas not points. |
| Pressure test. | Which branch of a system leaks. | Does not give an exact spot. |
| Tracer gas. | Pinholes in buried or enclosed pipe, slab leaks. | Needs a drained line and specialized equipment, adds cost. |
Practical notes.
Safety and what the technician needs from you.
Tracer gas work is safe when it is done by someone with the right equipment. The mix is diluted, the pressure is low and the area is ventilated. Pets and people can stay in the house, though the technician may ask you to keep clear of the work area.
To prepare, clear access to the floors and walls along the suspected run, and tell the technician what you have already tried. A meter reading, a stain location or a record of a past repair narrows the search a great deal. If the water bill has doubled, bring the last few bills, since the date it started can point to the run.
Decision guide.
When tracer gas is worth considering.
- The meter proves a leak, but acoustic and thermal tools have not found it.
- The leak is under a slab, a tile floor or a finished area where opening the surface would be expensive.
- The leak is in a long run of pipe and you need to narrow it before excavation.
- A previous repair attempt missed the source.
Many Salem houses have basements and not slabs, so the pipes are often visible or accessible from below, and simple tools work well. That is a reason to start there and spend more only if you must. A service line leak in the yard is better found with a combination of acoustic tools and, if needed, water line repair excavation at the marked point.
What this means for Salem homes.
Water reaches Salem homes through the Salem and Beverly Water Supply Board's mains, and the Board lists a Salem distribution number, 978-745-9595 extension 5673, on its water quality report for questions about service. If your meter shows a leak and your plumber finds the house side tight, that number is the place to ask about the street side.
Salem also has additions, garages and slab-on-grade rooms built onto older houses, and those are the likeliest places for a slab leak. A basement house with accessible pipes seldom needs tracer gas. If you have a heated slab or a finished room over a slab, ask a plumber whether it applies.
We serve homes across the area, including Beverly, and can tell you early whether your case needs more than the standard tools.
Safety.
What to do if you suspect a leak.
- Close the main water valve if you see water spreading.
- Do not drill or cut into a wall to look for the leak yourself.
- Photograph stains and note meter readings so the plumber can narrow the search.
Questions.
Helium leak detection questions from Salem homeowners.
Yes. Helium is non-toxic and not flammable. Hydrogen mixtures used for tracing are diluted to a safe level.
No. The line is filled at low pressure and the gas leaves when the test is over.
No. Most leaks are found with meter tests, acoustic and thermal tools. Tracer gas is for hard cases.
The line is isolated for the test. After the test, it is refilled and flushed.
Drain leaks are usually found with a camera or a smoke or dye test. Tracer gas is mainly for pressurized supply lines.