Water main leaks are problematic for city workers and also for homeowners. Cities face the loss of precious resources, which can be hazardous in areas already facing drought conditions. Homeowners can suffer damage to property and unexpectedly high bills.
Signs of Water Leaks in Plumbing
Water leaks can often go unnoticed for weeks or even months. Knowing the signs of a potential water leak help homeowners repair the problem quickly.
High Water Bills
The most obvious indicator of a leak is a high water bill when there has been no significant water consumption at the property. Leaks continuously pump water into the surrounding area causing the increase in cost.
Puddling on Property
Another visible sign of a leak is water puddling in the street or yard. A crack in the pipe allows water to flow into the soil, which eventually rises to the soil's surface, causing puddles in the yard. Leaks can also find cracks in the roadway enabling the water to flood streets.
Sometimes the leaks are smaller and less noticeable. Since the leak is insignificant, puddles do not form, and there is no significant change in the water bill. However, there is still an indicator for homeowners to take notice, moss growth.
If moss is suddenly taking over the yard, it is an indication that the soil is unusually wet. If there have never been any drainage issues in the past, it may be time to look for a leak in the water lines under the surface.
Sounds of Water Dripping
Finally, water leaks sometimes occur under the home. Residents may notice the sound of constant running water. The noise may also manifest as bubbling, banging, clanking or whistling even when no water is in use.
Inspecting Pipelines for Leaks
Trenchless technology allows professionals to examine lines and locate leaks without the costly and destructive method of digging up all the water lines. This is known as open trenching.
A popular method is the use of robots for CCTV Inspection. These bots crawl the underground pipes sending back video and sensor data to their operator. The mounted camera can pan, tilt and zoom to get a full view of the tube. Many of these robots can travel thousands of feet of line without losing connection with their surface operator.
Some cities use the mounted acoustic sensor to determine whether a line is cracked. These sensors “listen” for unusual noises coming from the pipes below the surface. A series of algorithms process the audio to locate potential leaks. Workers compare repeated test data to previous data; changes between the two data sets also help determine leaks.
The newer technology of ground penetrating radar (GPR) can also help identify leaks. Technicians move a large detector over the ground surface. Anomalies on the screen may be an indicator that there is a crack in the underground pipe. (Learn more in "The View Underground: Ground Penetrating Radar.")
Methods for Trenchless Leak Repair
As with inspections, the development of trenchless technology reduces the downtime and cost of water repair. Many of these same techniques are used to maintain septic tanks as well.
One popular method is a cured-in-place pipe, also known as CIPP. This resin-saturated polyester or fiberglass cloth forms a tube within a pipe structure. The fabric is inverted and pulled through the existing line from an access point. Once in place, the resin cures using UV light, hot water or steam, forming a seamless tube. (Read on in "Why CIPP Is Growing Rapidly for Drinking Water Mains.")
The cloth can move around bends in the plumbing, creating a single smooth line instead of having multiple joints. The technique for inserting CIPP into the existing line is often called Pull-in-Place lining or pipe.
Using robots to inspect water mains is only part of their usefulness. Once workers locate the leak, operators control the robot in placing sealant over the damaged section. Often, technicians use two different robots, one to inspect the pipe using sensors and cameras and the other equipped with tools to help seal the leak. (Learn more in "An Overview of Robotic Pipe Repair.")
For extensive damage, repairing the line may not be an option. Instead, workers may have to replace the pipe entirely. The trenchless method of pipe bursting requires more of an excavation process than other ways. However, once accessed, the bursting head breaks up the existing line while pulling the new pipe in place behind it. Often, workers use this method to replace older water mains with larger diameter pipes. (Learn more about this method in "An Introduction to Pipe Bursting.")
Knowing what to look for can help property owners discover water leaks and resolve them quickly. Trenchless methods are fast and efficient ways to address line damage. New technologies arise every day that make it easier to “see” the cracks without digging up the lines. With repair techniques such as CIPP, repair time is a fraction of what traditional methods would be, saving both the city and homeowners money.