SubSurface Leak Detection Inc

- Model LD-18 - Digital Water Leak Detector



The new LD-18 Digital Water Leak Detector is the first water leak detecting instrument to offer automatic noise reduction from intermittent interfering noises, like passing vehicles, people talking, and pedestrian footsteps.

  1. Amplifier with LCD Display, Controls, and USB Connection (to PC Computers)
  2. Padded Case for Amplifier
  3. 40 inches Belt (50 inches and 60 inches Optional)
  4. Ground Microphone and Handswitch
  5. Magnet Base and Nutdriver
  6. Heavy-Duty ABS Plastic Carrying Case
  7. Aviation-Grade Stereo Headphones
  8. PC Software and USB Cable

  • Sensor with Strong Magnet and 9.75 ft. Cable (to listen at valves and hydrants)

All-digital amplifier with automatic noise reduction of intermittent sounds, high and low filters, storage and graphing of sound levels at different locations on the pipe, bar graph and numeric display of sound loudness, USB connection, and back light.

LD-18 Amplifier showing filter settings, bar graph and numeric display of sound loudness, and minimum sound level detected.

Automatic noise reduction capability for intermittent noises such as pedestrian footsteps, people talking, and passing vehicles.

5 High Frequency filters, 3 Low Frequency filters (plus Low filter OFF), and 2 Notch filters (plus Notch filter OFF) to remove continuous interfering noises from A/C hum, motors, wind, etc.

Storage and graphical display of the leak‘s loudness at multiple locations along the pipe.

The “Saved” data file showing 10 leak sound levels and graphical display. Leak is at the peak sound level in the center.


  • Combined Sensitivity and Amplification :900 V/G or higher (at 400 Hz)
  • Low Filters :Off, 100 Hz, 200 Hz, 400 Hz
  • High Filters :400 Hz, 600 Hz, 800 Hz,
  • 1200 Hz, 2200 Hz
  • Notch Filters :Off, 50 Hz, 60 Hz
  • Maximum No. of Sound Levels Saved in File :250 (by date and time)
  • Power :4 C dry cell batteries
  • Battery Life (continuous use) :24 hours minimum
  • Weight :35 ounces (including 4 C batteries)
  • Size :6.4' x 3.0' x 5.7' (163mm x 76mm x 145mm)
  • Weather Resistance :IP52 equivalent
  • Temperature Range (Working) :Minus 4 F to
  • Positive 130 F


  • Type :Piezo electric ceramic
  • Weather Resistance :IP67 equivalent (3 ft water depth for 30 minutes)
  • Standard Base:3 - Pronged Plate(removable with nutdriver)

The loudness of a leak heard on an asphalt street or a concrete slab depends upon the size of the leak, water pressure, and depth of the pipe. Hard, dry materials like asphalt, concrete, rock, and compacted soil transmit sounds better than wet clay, sand, or loose soil. The sounds travel further on iron and steel pipes than on PVC pipes or Poly pipes.

Before listening on the asphalt or concrete over the pipe, always listen at hydrants, valves, and meters within 100 – 200 ft. of the suspected leak area:

Mark out the locations of the pipes and listen directly over them:

At the spot no. 1, do you hear the leak? If “Yes,” than the LD-18 hears the leak too. Hold the Mute Switch closed and let the LD-18 listen for 30 – 60 seconds or longer until the Minimum Noise Level becomes constant. Press the SAVE button while still holding the Mute Switch.

Repeat this exact same process for 5 – 10 spots directly over the pipe. Spots can be spaced 6 inches apart or 3 feet apart, but the LD-18 has to be able to hear the leak.

Each time the SAVE button is pressed (while the Mute Switch is closed), the Minimum Noise Level is recorded in the LD-18’s memory and a file number is assigned. Press FILE to see the File List, and press FILE again to see the GRAPH:

With the Minimum Noise Levels saved at 5 – 10 spots directly over the pipe, examine the GRAPH by pressing FILE twice:

The Minimum Noise Level at each spot is the actual leak sound, and where it reaches a peak is where the leak is pinpointed.

The Band Pass Filters (HI and LO Filters) and Notch Filters (Off, 50 Hz, 60 Hz) are used for removing extraneous continuous noises like AC hum (60 Hz in USA), motors, air conditioners, wind, and traffic. Extraneous noises can interfere with the LD-18’s ability to hear the leak sounds.

The Noise Reduction function removes intermittent noises like footsteps, passing cars, and dogs barking. Choose Lv.3 (3.0 sec.) to remove the longest lasting intermittent noises, up to 3.0 seconds long. Intermittent noises longer than 3.0 seconds cannot be removed.

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