Leak-Noise Correlation (Correlator) Detection
Leak-noise correlation is the most precise non-invasive method for locating leaks on pressurised water mains and service lines. Two acoustic sensors are placed at access points either side of a suspected leak; the correlator measures the tiny time difference between the leak sound reaching each sensor and calculates the exact position — usually to within a metre — without any excavation.
How leak-noise correlation works
A leak under pressure radiates sound along the pipe in both directions. By measuring the time-of-arrival difference at two sensors a known distance apart, and accounting for the pipe material's sound velocity, the correlator computes precisely where the noise originates. The result is a correlogram with a clear peak at the leak position.
Correlation vs. simple acoustic listening
Ground-microphone listening confirms a leak is present and roughly where. Correlation goes further: it pinpoints the position mathematically, works across longer pipe runs, and performs better in noisy environments and on buried mains where surface listening is ambiguous. We use listening to narrow the area and correlation to fix the point.
Noise loggers & overnight zone surveys
For larger networks we deploy correlating noise loggers across a pressure zone or district metered area (DMA).
Data-logging for large networks
Loggers record overnight when demand and background noise are lowest, then correlate automatically to flag the network section with an active leak — efficient for campuses, utilities and large commercial sites.
Pipe material matters
Metallic mains (ductile iron, copper, steel) transmit leak sound well and correlate excellently. Plastic mains (PE, PVC) transmit less acoustic energy and over longer distances; we adjust sensor spacing and frequency, and pair correlation with tracer gas where acoustic signal is weak.
Where this applies
- Municipal distribution mains and service connections
- Commercial and campus site-service loops
- Strata and multi-family buried water systems
- Industrial site water networks
What you receive
- Correlogram showing the calculated leak position
- Surface-marked location with depth estimate
- Pipe-material and confidence notes
- Written report for municipal, engineering or property records
Leak-Noise Correlation across Metro Vancouver & BC
We serve municipal water teams and clients throughout British Columbia — Metro Vancouver, the Fraser Valley, Vancouver Island and the Interior.
Frequently asked questions
How accurate is correlation?
On metallic pressurised pipe it typically locates the leak to within about a metre. Accuracy depends on pipe material, distance between sensors, and background noise — all of which we manage and report.
Does it work on plastic pipe?
Yes, with adjusted technique — closer sensor spacing and lower frequencies. Where plastic gives a weak signal we add tracer gas to confirm the location.
Do you need to shut the water off?
No. Correlation is performed on the live, pressurised system — the leak must be flowing to generate the sound we measure.
What is a noise-logger survey?
Loggers placed across a zone record pipe sound overnight and correlate automatically, identifying which section has a leak — ideal for large networks before detailed pinpointing.
Can you survey a whole pressure zone overnight?
Yes. Distributed loggers cover an entire DMA or campus loop in a single overnight deployment.
Get an exact leak position with correlation — request a survey.
LeakInspections.ca — a division of Anyleak.ca and the Leak.ca family. Professional, non-invasive leak detection across British Columbia since 1999. Call 604-239-9934.