Ways to Detect Underground Leaks

Causes of Underground Leaks

Tree Roots

Tree roots are a common cause of underground leaks, particularly in areas with expansive root systems. As trees grow, their roots seek out water sources, and if there are any existing small cracks or weaknesses in underground pipes, roots can infiltrate them. As roots continue to grow and expand, they may cause damage to the pipes, leading to leaks.


Corrosion is a natural process where metals deteriorate over time due to chemical reactions with the surrounding environment. Underground pipes made of materials like iron or steel are susceptible to corrosion, especially in areas with high soil acidity or aggressive water composition. Corrosion weakens the pipe walls, making them prone to leaks.

Ground Movement

The ground is subject to movements caused by various factors such as earthquakes, settling, or shifts in soil composition. These movements can put stress on underground pipes, leading to cracks or fractures. Over time, repeated ground movements can exacerbate existing weaknesses and result in leaks.

Water Pressure Fluctuations

Sudden and extreme changes in water pressure can stress underground pipes. Pressure spikes can occur due to events like water hammer (sudden stoppage or change in flow direction) or irregularities in the municipal water supply. These pressure fluctuations can compromise the integrity of the pipes, causing leaks to develop.

Signs You Might Have An Underground Leak

Unexplained Increase in Water Bills

One of the most common signs of an underground leak is a sudden and unexplained increase in water bills. If your water consumption patterns remain relatively consistent, but you notice a significant spike in your monthly water bill, it could be indicative of a hidden leak in your water supply line. An underground leak allows water to escape continuously, leading to increased water usage and, consequently, higher bills.

To investigate this sign, start by comparing your recent water bills to historical ones. If the increase is substantial and unrelated to changes in water usage habits, it’s advisable to conduct a thorough inspection of your property for potential leaks.

Low Water Pressure

A noticeable decrease in water pressure throughout your plumbing system may be a sign of an underground leak. When a leak occurs, water may escape before reaching its intended destination, resulting in reduced pressure at faucets, showers, and other water outlets. This phenomenon can be particularly noticeable in areas farther away from the water supply source.

To check for low water pressure, conduct a simple test by turning on faucets in various locations of your property. If you observe consistently low water pressure or notice a significant difference between different areas, it could indicate a leak in the water supply line.

Wet or Soggy Areas

The presence of wet or soggy areas in your yard, especially when it has not been raining, may be a clear indicator of an underground leak. Leaking water from a damaged pipe can permeate the soil, leading to the formation of damp or saturated patches on the ground’s surface. These areas may feel excessively soft, and you might observe the growth of mold, algae, or unexplained vegetation.

To investigate wet or soggy areas, visually inspect your yard for any unusual dampness. Pay attention to areas around the foundation, near water fixtures, and along the path of underground pipes. If left unaddressed, these wet spots can lead to further damage to landscaping, structures, and may even result in sinkholes.

Audible Water Flow

In some cases, you may be able to hear the sound of water flowing even when all water fixtures in your home are turned off. This audible water flow, often described as a hissing or rushing sound, can be an indication of a hidden leak. The sound may be more noticeable at night when ambient noise is reduced, making it easier to identify.

To check for an audible water flow, turn off all water-consuming appliances and fixtures, ensuring complete silence. Listen carefully in different areas of your property, particularly near known plumbing lines. If you hear the sound of running water when there should be none, it’s advisable to investigate further to identify the source of the leak.

Ways to Detect Underground Leaks

Detecting underground leaks is crucial for preventing water loss, minimizing environmental impact, and ensuring the efficient functioning of water distribution systems. There are various methods available for detecting these leaks, each with its own advantages and limitations. In this discussion, we will focus on two specific methods: using high-frequency ultrasonic listening devices and thermal imaging cameras.

High-Frequency Ultrasonic Listening Devices

High-frequency ultrasonic listening devices are widely employed in the detection of underground leaks due to their effectiveness in capturing the sound produced by water escaping from a pipe. This method relies on the principle that a leaking pipe emits ultrasonic frequencies that are beyond the range of human hearing. The high-frequency waves are generated by the turbulence of water as it escapes through the leak, and these waves can be detected using specialized listening devices.

The process begins with the deployment of ultrasonic sensors along the suspected pipeline or in the vicinity of potential leakage points. These sensors are designed to pick up frequencies ranging from 20 kHz to several hundred kHz, which are characteristic of water leaks. The collected data is then processed by sophisticated software that analyzes the ultrasonic signals, isolating the frequencies associated with leaks and filtering out background noise.

One of the key advantages of high-frequency ultrasonic listening devices is their sensitivity. They can detect even minor leaks that may go unnoticed through visual inspection or traditional methods. Additionally, this approach is non-intrusive, meaning it does not require excavation or disruption of the ground to identify the leak location accurately.

However, it’s essential to consider some limitations. Ultrasonic detection effectiveness can be influenced by environmental factors, such as ambient noise and the type of soil covering the pipes. Moreover, the method relies on the assumption that the leaks produce detectable ultrasonic frequencies, which may not be the case for all types of leaks.

Thermal Imaging Cameras

Thermal imaging cameras offer a different perspective on leak detection by capturing infrared radiation emitted from the surface of an object. When it comes to underground leaks, temperature anomalies caused by water escaping from a pipe can be detected using these cameras.

In this method, a thermal imaging camera is used to scan the ground surface above the suspected pipeline. Water escaping from a leak tends to have a different temperature than the surrounding soil. The camera captures the variations in temperature and translates them into a visual display, allowing technicians to identify potential leak locations.

The advantage of thermal imaging lies in its ability to detect leaks based on temperature differences, regardless of the type of material covering the pipes. It can be particularly useful in scenarios where ultrasonic detection may face challenges due to environmental noise or interference.

However, thermal imaging also has its limitations. It may not be as effective in detecting small leaks, and false positives can occur due to factors such as variations in soil moisture or surface conditions. Additionally, this method requires favorable weather conditions, as rain or extreme temperatures can affect the accuracy of the thermal readings.

Other Methods for Underground Leak Detection

Besides high-frequency ultrasonic listening devices and thermal imaging cameras, there are several other techniques commonly used for detecting underground leaks:

Acoustic Leak Detection

This method involves using microphones to listen for the sounds generated by water escaping from a leak. The sound waves are then analyzed to pinpoint the leak location. While less sensitive than high-frequency ultrasonic devices, acoustic leak detection is suitable for a wide range of pipe materials.

Ground Penetrating Radar (GPR)

GPR utilizes electromagnetic waves to create subsurface images. By emitting radar pulses into the ground and analyzing the reflected signals, technicians can identify anomalies that may indicate the presence of a leak. GPR is effective for locating leaks and mapping underground utilities.

Tracer Gas Leak Detection

Tracer gases, such as helium or hydrogen, are injected into the water pipe. If there’s a leak, the tracer gas will escape to the surface, and specialized sensors can detect these gases. This method is highly accurate and is often used in conjunction with other detection techniques.

Pipe Inspection Cameras

Fiber optic cameras can be inserted into pipelines to visually inspect the interior for signs of leaks, corrosion, or damage. This method is particularly valuable for assessing the condition of pipes and identifying potential issues.

Pressure Testing

By pressurizing a section of the pipeline and monitoring pressure changes, technicians can identify areas with leaks. Pressure testing is effective for both pinpointing leak locations and assessing the overall integrity of the pipeline.

The evolving array of advanced technologies and innovative methodologies for detecting underground leaks underscores the critical importance of safeguarding our essential plumbing systems. As we navigate an era of increasing demand for resources and environmental sustainability, these diverse and interconnected solutions not only enhance the precision and speed of leak detection but also contribute to the resilience and longevity of your plumbing systems. Seek help of a trusted plumbing professional to inspect your leaks.