How to Locate an Underground Water Leak

How to Locate an Underground Water Leak

Water leaks, especially those underground, pose significant challenges to water utility managers and property owners alike.

Unnoticed or unresolved, these leaks can lead to substantial water loss, structural damage, and increased operational costs. In the realm of water management, non-revenue water (NRW) loss refers to water that is produced but never reaches the end user due to leaks, theft, or metering inaccuracies. It’s vital to locate underground water leaks using advanced techniques and tools such as acoustic leak detection and leak detection correlators, to mitigate NRW loss and keep your water infrastructure working for you.

Water bursting from a unearthed pipe.
It’s vital to locate underground water leaks using advanced techniques and tools such as acoustic leak detection and leak detection correlators, to mitigate non-revenue water (NRW) loss and keep your water infrastructure working for you.

Understanding Non-Revenue Water Loss

Non-revenue water loss is a critical issue in water management. It encompasses any water that does not generate revenue, primarily due to:

  • Leaks: Unintended water escape from the distribution network, which can occur in pipes, joints, or valves
  • Theft: Unauthorized connections or tampering with the water supply
  • Metering Inaccuracies: Faulty meters that do not accurately record water usage

Leaks are the most common cause of non-revenue water loss, particularly those that are underground and hard to detect. Identifying and fixing these leaks not only conserves water but also improves the efficiency of water distribution systems.

Signs of an Underground Water Leak

Before diving into detection techniques, it's essential to recognize the signs indicating a potential underground water leak:

  • Unexplained Water Bills: Sudden increases in water bills without a corresponding increase in usage
  • Wet Spots or Water Puddles: Persistent wet areas in your yard or around your property, especially during dry weather
  • Decreased Water Pressure: Noticing a drop in water pressure, indicating a possible leak in the supply line
  • Sound of Running Water: Hearing water running when all taps are closed can be a sign of a hidden leak
  • Cracks in Foundation: Structural damage like cracks in walls or floors may be due to water eroding the foundation
A GPRS Project Manager conducting leak detection services in a field.
GPRS’ water loss specialists have the equipment and expertise to locate your leak and provide insights into your water distribution system.

Techniques for Locating Underground Water Leaks

Acoustic Leak Detection

Acoustic leak detection is a popular method that involves listening for the sound of water escaping from pipes. This technique relies on specialized equipment to detect the acoustic vibrations generated by leaks.

How It Works: As water leaks from a pipe, it creates a distinct noise. Acoustic leak detection devices, such as ground microphones and listening rods, amplify these sounds, allowing technicians to pinpoint the leak’s location.

Equipment Used:

  • Ground Microphones: These are sensitive devices placed on the ground surface to listen for leak sounds
  • Listening Rods: These are used to directly contact exposed pipes and listen for leak vibrations


  • Investigate: Technicians investigate the area with ground microphones to identify the general vicinity of the leak
  • Pinpoint: Using listening rods or more focused ground microphones, they narrow down the precise location


  • Non-Invasive: Does not require digging or disruption of the surface
  • Accurate: Can pinpoint the exact location of leaks with high precision

Leak Detection Correlators

Leak detection correlators are advanced devices that use the time difference in sound waves traveling through the pipe to locate leaks.

How They Work: Two or more sensors are placed at access points along the pipeline. These sensors detect the noise from the leak and send data to a central unit. The correlator calculates the leak’s position based on the time delay of the sound waves reaching each sensor.

Equipment Used:

  • Sensors: Placed on pipe fittings or access points to capture leak noise
  • Central Unit: Analyzes data from the sensors to determine the leak location


  • Placement: Sensors are strategically placed on the pipeline at known access points
  • Data Collection: The sensors transmit noise data to the central unit
  • Correlation: The central unit processes the data to calculate the leak’s location based on the difference in sound wave arrival times


  • Highly Effective: Particularly useful for long or complex pipeline systems
  • Real-Time Data: Provides immediate feedback on the leak location

Other Methods

While acoustic leak detection and leak detection correlators are prominent techniques, other methods also play a role in locating underground water leaks:

Ground Penetrating Radar (GPR)

How It Works: GPR sends radar pulses into the ground and measures the reflected signals to identify changes in the subsurface. This can detect buried pipelines and cavities caused by leaks.

Advantages: Useful for detecting leaks in non-metallic pipes and identifying subsurface anomalies.

Infrared Thermography

How It Works: Infrared cameras detect temperature variations on the surface caused by leaking water. Cold or warm spots can indicate the presence of water leaks.

Advantages: Non-invasive and effective for identifying leaks in heated or chilled water systems.

Locating an Underground Water Leak

Step 1: Confirm the Presence of a Leak

Before deploying advanced detection techniques, verify that a leak exists. Check your water meter for continuous movement when all water fixtures are off.

Step 2: Investigate the Area

Conduct a visual and acoustic evaluation of the suspected leak area. Look for visible signs and use ground microphones to listen for leak sounds.

Step 3: Use Advanced Detection Equipment

Deploy acoustic leak detection devices or leak detection correlators to pinpoint the leak’s location. Follow the specific procedures for each method to ensure accurate results.

Step 4: Validate and Repair

Once the leak is located, verify its position by minimal excavation or exposing the pipe. Proceed with the necessary repairs to fix the leak and restore the integrity of the water system.

Preventing Future Leaks

To minimize non-revenue water loss and prevent future leaks:

  • Regular Inspections: Schedule routine inspections and maintenance of your water distribution system
  • Pressure Management: Maintain optimal water pressure to reduce stress on pipes and fittings
  • Pipeline Monitoring: Use remote monitoring systems to detect early signs of leaks or pressure drops

GPRS’ water loss specialists have the equipment and expertise to locate your leak and provide insights into your water distribution system. We utilize a variety of industry-leading equipment and methods, including acoustic leak detectors, leak noise correlators, video pipe inspection, ground penetrating radar, and electromagnetic (EM) locating.

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