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Why the Method Is Called Listening

Water escaping a pressurized pipe makes a noise. Everything acoustic detection does follows from that sentence, including the things it cannot do.

The essentials

Acoustic listening works by hearing pressurized water escaping, so it is strongest on metal under pressure and weakest on plastic, on low pressure, and on drain lines that carry no pressure at all. That limit is physics rather than equipment quality.

AcousticLeak is a referral service, not a contractor. We connect homeowners with independent contractors. Contractors are required to hold whatever credential their state or municipality demands. We carry out no work and no leak location, we do not set prices, and we never charge homeowners anything — the contractors in our network pay us when we route them a call. Nothing here is a statement about what your own utility will credit; only your utility can tell you that.

Pressure is what makes the sound

A pipe under pressure with a hole in it pushes water out through the hole, and the water and the pipe wall vibrate. That vibration travels along the pipe and through whatever surrounds it, and a sensitive microphone placed on the ground, on a fitting or on a valve can pick it up.

The consequence is immediate and it is the most useful thing on this page: a drain is not pressurized, so a drain leak makes no such noise. If the problem is waste water rather than supply water, listening is the wrong tool and a camera is the right one.

Why a supply leak can be heard and a drain leak cannotTwo pipes drawn in section. The upper one is a supply pipe, shown full of water under pressure, with a hole in its underside and sound waves radiating from it. The lower one is a drain, shown with water lying only along its floor at atmospheric pressure, with a hole and no sound.SUPPLYfull, under pressurewater is forced out, and that makes a noiseDRAINpart full, no pressurewater falls through, and there is nothing to hear
Everything acoustic detection does follows from the top half of this drawing. If the problem is waste water rather than supply water, listening is the wrong instrument and a camera is the right one.

What the pipe is made of changes what you can hear

Metal carries sound a long way. Rigid plastic carries it less well and flexible plastic less well again, so a leak on a plastic service line can be audible only within a few feet of itself, if at all. Depth, soil, backfill and whether the line runs under a slab or under a lawn all change the answer too.

This is why an honest operator asks what the pipe is before quoting a survey, and why one who does not ask is worth a second question.

The other instruments in the van

A correlator listens at two points at once and uses the difference in arrival time to compute where between them the noise began. A tracer gas rig charges the line with a hydrogen and nitrogen mixture and finds where it surfaces, which works when there is no useful sound at all. A thermal camera sees a warm floor over a hot line. A ground microphone is the classic tool and still the fastest on metal.

None is universal. The reason a survey is quoted rather than priced from a list is that which of these is appropriate depends on the pipe, and nobody knows that before they arrive.

What a locate is not

Locating is not repairing and it is not a warranty. It narrows where to open the ground or the floor, which is worth a great deal when the alternative is opening it speculatively, but the ground can still be opened and the leak found a foot away.

Ask how that case is handled before the work starts rather than afterwards. The questions worth asking are on their own page.

Next

Check with your water utility first.If the leak is on their side it is not your bill and not your excavation, and that call is free. If it is yours, come back and we will route you to a local contractor who can find it, chosen on the ZIP code you give. We never charge you either way. Nor must it be a leak: whatever the plumbing is doing, this number reaches somebody.

Call (888) 530-1544
Call (888) 530-1544