How to locate underground water lines? Professionals use the electromagnetic and Ground Penetrating Radar (GPR) to locate subsurface water pipes. They use either one (or both) depending on the soil condition and other factors.
In this comprehensive article we’ll discuss each method. We’ll also mention about the importance of locating underground water lines before doing any construction and excavation work. Let’s start.
Why locate subsurface water pipes?
Failure to do this may result to injuries, fatalities and damage to properties. That’s because when water pipes are damaged, the high pressure released might propel debris to people and the surroundings.
As a result, the following things may occur:
- Debris and water injures nearby people
- Flooding of the area due to release of water
- Delay of the excavation or construction activity
- Increased costs because of the delay
- Possible redesigning of the project
- Legal issues due to interruptions to the community
These are all costly and time-consuming. It may even result to the permanent halt of the project. That’s why engineers and developers first consider the location of water pipes and other subsurface infrastructure before commencing any excavation or construction activity.
For instance, many construction companies contact us here at One Search Locators. Our expert team locates the following:
- Underground water pipes
- Electricity lines
- Sewer lines
- Storage tanks (used for oil refinery or gas service station)
- Gas pipes
- Telecommunication cables
- Voids (soil has been washed away under concrete slabs or rocks)
- Storm water drains
Engineers and developers contact us to pinpoint the location of underground water lines and other utilities for the following reasons:
- Prevent injuries, fatalities and damages
- Prevent or minimise project delays
- Speed up the construction or excavation activity
- Proper planning of the work schedule and timeline
- Prevent redesigning because all relevant information are present before planning
- Prevent legal ramifications
How professionals locate water pipes?
Whether it’s for residential, commercial, industrial or government project, underground water pipes should first be located to eliminate the risks of blind digging. After all, one mistake is enough to cause cascading problems to the construction company and developer itself.
That’s why professionals use specialised methods and tools to solve the problem. They commonly utilise:
- Electromagnetic method
- Ground Penetrating Radar (GPR)
As mentioned earlier, professionals use either or both of the methods to fully locate the complex network of water lines underground. That’s because each method has its own weaknesses and strengths.
Electromagnetic method for water utility mapping
Basically, the electromagnetic method sends electromagnetic signals and then using the readings to locate the pipes. A transmitter and receiver are used for this purpose.
This is a targeted means of detecting and locating metallic pipes. The signals being transmitted are adjusted to specifically respond to the metal pipes (hence isolating the target) while separating it from other objects underground.
First, the signal should get onto the line and make it stay until the whole target line’s finished. Take note that there are other subsurface utilities (whether active or not) that might interfere with the job. This is a huge challenge because the signal could spread onto other lines that might not be of interest (e.g. companies only concerned with water pipes).
It’s a straightforward approach. However, these potential issues might make utility mapping far from 100% accurate:
- Multiple utilities are grounded together (which is which?)
- Abandoned utilities might also be present
- Lack or absence of access points (signal should first get onto the line and follow through)
These challenges make professionals perform other procedures to ensure accuracy in locating underground pipes. For example, they might use old records and documents to have an idea about the history and present condition of the site. It’s often just a starting point so professionals will have additional information.
Professional utility locators also ask for full information regarding the work area. This way, locators can only focus on locating pipes and other utilities within the site. They can then use the proper access points and isolate the pipes located underground from the outside work area.
It’s also important that the firm only hires experienced and highly qualified locators for the job. As discussed earlier, the electromagnetic method is for detecting metallic pipes underground. It won’t work well with PVC pipes or lines without tracer lines. That’s because the electromagnetic signal can only follow through metallic pipes.
If this is the case, Ground Penetrating Radar is used to locate non-metallic utilities (and also metallic pipes). Professional utility locators might also use this in conjunction with electromagnetic method to get more information about the subsurface infrastructure.
Ground Penetrating Radar (GPR)
GPR works by sending electromagnetic signals and then detects the reflected signals from the pipes and lines underground. From the term itself, it uses radar pulses to transmit and interpret the data being reflected (just like the common radar for detection purposes).
As mentioned above, GPR is also good in detecting and locating non-metallic utilities. That’s because GPR responds to almost all relevant buried objects. When the GPR transmitter emits energy into the ground, the electromagnetic energy will be reflected, refracted or scattered back to the receiving antenna. The return signal will show variations as a result of different permittivities of the materials detected underground.
In other words, different objects provide different data which professionals can use to identify those objects. This is also a straightforward approach just like the electromagnetic method discussed earlier.
Because of the functionality and reliability of GPR, professionals also use the method to detect the following:
- Underground storage tanks
- Possible geologic hazards
In addition, the GPR method can penetrate up to 30 metres underground during ideal conditions (dry soil). This is very valuable in large-scale excavation and construction projects. However, wet soil and high conductivity materials might interfere (absorb or reduce) the GPR signals before or while encountering the target objects and materials. Moreover, GPR might take longer for all the data to be gathered, processed and interpreted. In these kinds of challenges, experienced professionals are needed the most to provide the most accurate data before any excavation and construction begins.
How professional locators address the challenges
Both the electromagnetic and GPR method have their strengths and weaknesses
- Electromagnetic method (EM) can be faster
- EM only allows detection of metallic pipes
- GPR detects both metallic and non-metallic utilities
- GPR can be slower
Often, both time and accuracy are crucial in the successful execution and completion of any project. For better accuracy, we need more time. For faster progress, accuracy might be compromised.
However, accuracy should not be sacrificed at all costs. You might save time initially, but the compromise and the resulting mistakes will consume more time than expected. Add to that the increased costs for the digging and building.
That’s why here at One Search Locators, we prioritise accuracy at all costs. We understand the risks of blind digging. Excavation or demolition without knowledge of subsurface utilities can lead to injuries and costly delays. We also have the objective of ensuring a safe workplace for the crew.
Even with the use of advanced tools and technologies, expertise is still the way to ensure accuracy and efficiency. After all, the proper use of electromagnetic and GPR method is the one that leads to accurate results. Professional locators understand the weaknesses and strengths of the methods. As a result, they know which one to use in a particular situation. They also know how to maximise the strengths of these technologies.
Locate underground water lines Sydney
Here at One Search Locators, our goal is to provide accurate data and a complete picture of the subsurface utility map. We have accomplished this for our clients through:
- Use of specialised tools and technologies
- Use of our expertise in working in all types of projects (residential, commercial, government)
- Use of all relevant data to enable comparison and referencing
- Use of strong measurement and recording procedures to ensure accuracy for interpretation
As a result, many firms in Sydney and Melbourne have already requested us to map the underground utilities before commencing any construction or excavation activity. The information we provided has also helped them create proper plans that consider all the risks underground.
Contact us today if you need a detailed and accurate utility map for your project. We provide fixed rates and we can arrive at your site within 24 hours for faster progress. Our certified Service Locators will be ready to assess your work area.