Leak Correlator vs. Leak Detector: a comparison article

In this article, we will cover water leak detection equipment: specifically, water leak detectors and water leak correlators. Each type of equipment will be defined, and their strengths and weakness will be reviewed. We will then cover how to choose the right detection equipment for your organization’s needs, followed by links to popular products for each solution.

Water Leak Detection and Correlation: Why is it necessary?

Municipal water supply systems are complex and often encompass hundreds of miles of pipelines. With such large systems that are often built with sections of variously aged pipes, leaks are bound to happen. A few small leaks here or there are expected, and generally do not pose major problems. However, as a few leaks develop into a few dozen, and then a few hundred, they can cause a large aggregate water loss, a significant drop in system water pressure, and can increase the likelihood of contamination in customers’ water supply lines.

Many water supply systems are equipped with pressure sensors that will alert management if a large loss of pressure is detected on a line. However, if numerous small leaks appear gradually, or if a single small leak gradually grows, the pressure loss may go unnoticed.

Water Leak Surveys, Audits, and Pinpointing are the Solution

Due to the potential for system wide water loss and, in extreme cases, failure of a water supply system entirely, all municipal water supply organizations should have water leak audits and surveys as part of their regular maintenance plans.

Water Leak Surveys and Audits

“Water leak survey” and “water leak audit” are often used interchangeably. During a water leak audit, a system is systematically surveyed for water loss. A survey may incorporate the entire water supply system at once, or it may be done on a neighborhood-by-neighborhood basis. The initial leak survey is generally not designed to identify individual leak locations, but to determine which water supply lines are likely to have leaks.

During a water leak audit, leak detection can be conducted with either a leak correlator or a leak detector. Each of these devices detects water line leaks acoustically and both tools are designed to conduct water leak surveys on a system wide basis.

Water Leak Pinpointing

Once sections of pipeline with leaks are determined, individual leaks will need to be pinpointed for repairs. This is a separate task from a water leak survey and can be completed after the system has been fully audited. Pinpointing can be done acoustically with either a leak correlator or a leak detector.

Leak Correlators and Detectors are essential equipment for conducting water leak audits and surveys

Water leak correlators and water leak detectors are both acoustic listening devices for conducting water leak surveys and pinpointing individual leaks. However, there are significant differences in the way they operate and the results that they produce.

Water Line Leak Detectors

Water line leak detectors are acoustic listening devices. Think of a leak detector as a “stethoscope” for listening for leaks in a water supply system. All acoustic water line leak detectors incorporate three main components: a microphone, an amplifier, and headphones.

The Leak Detector Microphone: The microphone is placed directly on the ground surface above a pipe to pinpoint leak locations. Many units are equipped with connections for contact rods or magnets which increase the range of listening locations to include below ground level, valves, and hydrants. Most microphones are integrated with piezoelectric crystals. When these crystals interact with sound waves, they generate a small amount of electricity which is passed through a cable into the amplifier. 

The Leak Detector Amplifier: Amplifiers are an integral part of any acoustic water leak detection device. Even with extremely sensitive ground microphones, the sound of a leak can be well below the range of human hearing. Powerful amplifiers allow the signal received from the ground microphone to be multiplied hundreds of times and into the audible range.

The Leak Detector Headphones: The amplified signal from an acoustic leak detector’s ground microphone is finally passed into headphones worn by the user. The use of headphones is critical to the successful use of these devices. Even after amplification, the sounds of leaks can still be very low and just within the audible range. Headphones also decrease distractions from noise in the surrounding environment such as traffic, footsteps, and construction.

While all acoustic leak detection devices have the basic components listed above, there are various additional features added by manufacturers to increase the utility of the device. These range from digital and analog meters to computers that can store readings.

Water Leak Correlators

Water leak correlators are also acoustic listening devices, however whereas the sounds collected by a leak detector are interpreted by a human operator, in a leak correlator, they are interpreted by a computer processing unit. The computer collects noise data from multiple water lines at once and can correlate the data to identify not only which lines are leaking, but the exact distance to the leak locations. Water leak correlators have two primary components, the Main Processor Unit, and a series of Pre-Amplifier Transmitters.

The Leak Correlator Main Processor Unit: The main processor unit is the heart of a leak correlator. During a water leak audit, the size, material, and water pressure of the pipeline being audited are entered into the processor. When the sounds of leaks are collected by the pre-amp transmitters and sent to the main processor unit, they are interpreted by computer-based algorithms to precisely locate leak locations along the pipeline system. The leak location data is then displayed on the screen of the main processor unit.

The Leak Correlator Pre-Amp Transmitter: The pre-amp transmitters collect leak noise data for the main processor unit to use. These units are placed inside the water system at different locations. At each location the sound of water running through the lines is recorded. The location of each transmitter is also recorded by GPS. All of this data is then sent to the main processor unit by radio signal for processing.

Strengths and Weaknesses for Water Leak Detectors and Leak Correlators

Water leak detectors and correlators both have survey conditions where one device will outperform the other. The following is a brief discussion of the strengths and weaknesses of each type of acoustic leak detection device.

Water Leak Detectors

Water leak detectors are very effective tools for water leak surveys and for pinpointing individual leaks after a survey has been conducted. With powerful ground microphones and noise filter functions, a skilled operator can quickly survey individual pipelines throughout a system to determine leak locations.

Like most tools, an acoustic leak detector is only as good as the user behind it. The more experience an operator has, the more likely leaks are to be correctly identified. Unlike the leak correlator, a leak detector relies solely on the skill of the operator. In addition, it can only effectively survey one pipeline section at a time.

Water Leak Correlators

Water leak correlators are perfect tools for surveying multiple pipelines at once and for identifying leak locations with pinpoint accuracy. Since the data is collected by the pre-amplifiers and interpreted by computer-based algorithms in the main processing unit, the potential for user error is reduced. Water leak correlators are best used in busy city environments where loud noises can overwhelm a human listener or where multiple water lines need to be audited at once.

Water leak correlators can be more complex to set up than a leak detector. With multiple pre-amplifiers spread across several city blocks, choosing the right listening location is important. In addition, GPS satellite connections and radio communication connections must be established and kept clear. Once these are established, however, determining precise leak locations is completed by a computer program.

How to Decide between a Leak Correlator and a Leak Detector

It is important to choose the correct piece of equipment for your water leak survey project. Leak detectors and leak correlators can both save tens of thousands of dollars in system costs and repairs over their lifetimes, but they pose a significant initial capital investment. Taking into account the following considerations can help you to choose the correct leak survey device for your projects.

Determine your water leak survey environment: Water leak detectors work best in quiet neighborhoods or on small city streets. Water leak correlators work on busy city streets with lots of traffic noise. They also work well in quiet environments.

Determine your operators’ skill set: Water leak detectors are acoustic listening devices that rely on operators to interpret leak sounds by ear and visual meters. It can take time for new users to develop enough experience to correctly identify leak locations with a leak detector. If you have new users, it is best to send them out with an experienced operator for training.

Water leak correlators interpret leak location sounds using computer programs. This can reduce the potential for user error and the need for training on the interpretation of signals. However, setting up a leak correlator can be more complex than using a leak detector. If using a leak correlator, be sure that the user is comfortable with making connections to GPS systems and radio-based systems.

Determine your budget: Leak detection equipment represents a significant investment. Acoustic leak detectors can range from the low to mid thousands of dollars per unit. Leak correlators can run between 20 and 30 thousand dollars per unit. If you will only be using the unit very rarely, or once, consider finding a leak detection service or renting the leak location equipment instead of buying.

Recommended Leak Correlator and Leak Detectors

The following are recommended products carried by Precision Outdoor Tech for leak correlation and leak detection. Product pages for all of these products can be found our Leak Detectors collection page

Leak Detectors

The LD-7 Leak Detector: This is our most economically priced leak detector. It is designed primarily for leak pinpointing activities. It is also our most compact leak detector and can easily fit behind the seat of a work truck.

The LD-8 Leak Detector: This is our most economically priced leak survey device. Designed primarily for leak audits, this device also has an LCD screen which displays readouts of how loud a leak sound is. This helps to eliminate guesswork when determining leak locations.

The LD-12 Leak Detector: This is our most popular leak detector. It is designed to conduct leak surveys AND leak pinpointing. With additional noise filtering functions, the LD-12 can also work in areas with significant background noise.

Leak Correlator

The LC-5000 is the ONLY leak correlator carried by Precision Outdoor Tech. This device is available in two packages: the two pre-amplifier package or the four pre-amplifier package. With GPS location technology and a powerful main processing unit, this correlator is designed for busy city streets and provides precise leak locations during water leak surveys and audits.

Contact us with any Leak Detector or Leak Correlator Questions

At Precision Outdoor Tech, we want to make sure that you find the leak survey or audit device that meets the needs of your project. Give us a call with your question, and we will be happy to help you out. If we don’t’ know the answer, we will find it for you. If it is after hours, please use the contact form listed in the municipal contact section directly below and we will respond shortly.

Please follow the link to our product page collection below if you would like to compare our leak detection and correlation devices.

Leak Detectors Collection Page