How Do Plumbers Detect Leaks

A Leak in a PipeThere are a number of ways that plumbers are able to detect hidden leaks in and around a home. These methods involve carefully inspecting a home’s hot water, toilets, meter and hose-bibs, as well as other various fixtures and valves. Leaks are often very difficult to locate and some of these methods allow a plumber to find the approximate location of a leak.

However, by using their knowledge, skills and intuition, a plumber can pinpoint the exact location of the hidden leak and take measures to address the problem.


The first way that a plumber may try to detect a leak is to check the pressure relief valve on a home’s hot water tank. There are times when this valve is attached directly into a drain and might be leaking. A plumber will remove the drain pipe to determine if there is a leak. In cases where the drain pipe is difficult to remove, a hissing sound may indicate that there is indeed a leak.

A plumber may also inspect for leaks in the home by taking off a toilet’s lid and listening for this hissing noise. At that point, the plumber will determine the location of the hissing noise so that they can fix the leak. If there is more than one toilet in the home, the plumber may repeat this process with each toilet to ensure that there are not multiple leaks.

The Line

If the plumber has determined that the toilets are running properly, they will review the line that connects the meter and the house. Once the shut-off valve is temporarily turned off, the plumber will review the meter to see if it is still turning. If this is the case, this will indicate that the leak is between the house and the meter. Therefore, the plumber will inspect the ground between the shut-off valve and the meter for obvious signs of a leak such as wet grass and mud.

On the other hand, it may be determined that the shut-off valve is leaking, which indicates that the leak is actually within the home. At that point, the plumber will attempt various techniques to pinpoint the location of the leak.


Finally, a plumber will attempt to detect leaks by inspecting the hose-bibs outside of the house. Most homes have a hose-bib in both the front and back yard, so the plumber will carefully inspect each of these. The plumber will listen to the hose-bib to determine if there is any sound at all. If either of the hose-bibs surrounding a house have a louder sound, that indicates that the leak is closer to that unit.

However, if the plumber is unable to detect any sound from either hose-bib, they will go into the house and carefully inspect all fixtures and valves for any sound to pinpoint the leak. This can include sink faucets, shower heads and valves, toilets, the washer and the hot water heater. The plumber may also return outside to see if there are any leaks in the hoses and irrigation systems that are used for gardening and lawn care purposes.

Charlie Teschner started MESA Plumbing, Heating, and Cooling in 1982. Charlie has a journeyman and master plumber’s license. He was raised with a strong work ethic and he now applies those values to all tasks with his team of Longmont plumbers.