Water and gas leak detection
Most leaks hide. Water gets into a wall or under a slab and shows up as a stain three rooms away. Gas gives you a smell and nothing else. We find both without turning your house into a demolition site, using cameras, infrared, moisture meters, ultrasonic listening equipment, pressure testing and gas detectors instead of a drywall saw. If you smell gas right now, read the first section before anything else on this page.
If you smell gas, get out and call from outside
Get everyone out of the house, and once you are well away from the building call 911 first, then your gas utility: Peoples Natural Gas at 1-800-400-4271 or Columbia Gas of Pennsylvania at 1-888-460-4332, both answered 24 hours. The full list of what to do and what not to touch on the way out is on our emergency service page, and it is worth reading now rather than in the moment.
Wahl is who you call to find and repair the leak after the house is safe and the utility has cleared it. That part is what the rest of this page is about.
A supply leak and a drain leak are found two different ways
Before any equipment comes out of the truck, the first question is whether the water is coming from a line that is under pressure or a line that only carries water when something is running. Those two behave nothing alike, and chasing one with the other's method is how walls get opened for no reason.
Supply lines are pressurized every second of the day. That means a supply leak never stops, it registers at your water meter even with every fixture off, and it makes a continuous high frequency sound that ultrasonic equipment can follow along the run. It also means we can test it. Shut the main, watch a gauge, and a line that will not hold pressure tells us something before we have touched a wall. Isolating branches from there narrows which run is failing.
Drain and waste lines are the opposite. They sit empty at atmospheric pressure and only leak while a fixture is draining, so nothing shows at the meter and there is no steady sound to chase. Those get found by running one fixture at a time and watching, by camera inspection inside the line, and by hydrostatic testing, which means plugging the line, filling it, and seeing whether it holds.
A third case sits in between. A hot water supply line under a slab or under a floor leaks constantly like any supply line, but it also gives off heat, which is why thermal imaging often finds it faster than anything else.
How we find a water leak without opening walls
The point of real detection equipment is to make one small, deliberate opening in the right place instead of five hopeful ones in the wrong places. Here is what we carry and what each piece does.
Most jobs use two or three of these together. Infrared narrows it to a wall, the moisture meter confirms it, ultrasonic pinpoints it, and then we open one spot. Before we start opening anything, we tell you where we intend to open and why.
- High definition camera inspection. We push a camera through drains, waste lines and the sewer lateral to see cracks, root intrusion, offset joints, bellies and separations, and to record what we find and exactly where it sits.
- Infrared imaging. Thermal cameras read temperature differences through finished surfaces. A leaking hot line under a slab shows as a warm track. Wet drywall and saturated insulation read cooler than the material around them.
- Moisture meters. They confirm what the infrared suggests and map the wet edge, which separates a live leak from surface condensation or an old stain that dried out years ago.
- Ultrasonic leak detection. Pressurized water escaping a pipe makes a high frequency sound you cannot hear standing there. Listening equipment tracks it along the run and narrows a slab or behind-tile leak down to a small area.
- Pressure and isolation testing. A gauge on the system with the main shut tells us whether the supply side is losing water at all. Closing off one branch at a time tells us which run is doing it.
- Hydrostatic testing on drains. Plugging and filling a waste line proves whether it holds, which is how a drain leak gets confirmed when there is nothing at the meter to measure.
- Line tracing and pipe locating. A transmitter on the line and a receiver above ground maps where your water service or sewer lateral actually runs, so if we do have to dig, we dig over the pipe instead of hunting for it.
- Dye testing. A traceable dye separates a toilet quietly passing water, an overflow, or a shower pan failure from a leak inside the structure.
- Electromechanical gas detection with leak detection solution. The detector finds where gas is present in the air. The solution bubbles at the exact joint, so the repair is a fitting rather than a whole section.
What a hidden water leak looks like before you ever see water
Water almost never announces itself where it is leaking. It follows framing, pipe runs and gravity, then shows up somewhere else entirely. These are the things worth calling about, especially in older Pittsburgh housing stock with original galvanized supply lines or cast iron waste.
One of these on its own may be nothing. Two or three together usually is something.
- A water bill that climbed with no change in how you use water.
- The meter dial creeping while every fixture in the house is off.
- A warm patch on a floor, which often means a hot water line under the slab.
- The sound of running water when nothing is running.
- A musty or mildew smell in a closet, a cabinet, or along a baseboard.
- Staining, blistering paint or a soft spot on a ceiling or wall.
- Water pressure that dropped off and never came back.
- Persistent damp in a finished basement that has nothing to do with the weather.
- A patch of lawn that stays green or soggy in a dry stretch, which can be the water service line under the yard.
The meter is the dividing line on gas
The responsibility line on gas is simple once you know where it sits. The utility owns and maintains the gas main and the service line up to and including the meter. Everything downstream of the meter, the piping running through your basement and up to your furnace, water heater, range, dryer and fireplace, belongs to the house. When the leak turns out to be on that side, the repair is yours to schedule, and that is our work.
For gas we use electromechanical combustible gas detectors to find where gas is present in the air, then leak detection solution on the joints to bubble up the exact fitting. After a repair we leak test the piping so the line is proven to hold rather than assumed to. We handle the permit and the paperwork the utility requires, and we relight and check appliances once the utility has restored service. Only the utility turns gas back on after a safety shut off. We never touch that.
We also run and replace gas piping for a furnace, a water heater, a range, a dryer, a grill line or a fireplace, and we can leak test an existing system on a scheduled visit if you simply want to know where your piping stands.
Find your main water shutoff before you need it
If water is actively running, shutting the main is the first move. Every minute the line stays under pressure is more water in your ceiling, and it is also the difference between a detection call and a restoration project.
That valve matters to the diagnosis too. Half of what we do on the supply side depends on being able to close the main and hold pressure on a gauge. In a lot of older Pittsburgh basements the original gate valve has not been turned in thirty years and will not seat when it finally gets asked to, which is something worth knowing on a quiet Tuesday rather than at midnight with water coming through a light fixture.
If you are a Wahl customer, there is a good chance you already have a Wahl valve tag on your main shutoff. We put those on so nobody is hunting through a dark basement in an emergency. If you do not have one, or you are not sure which valve is yours, ask your technician to tag it and walk you to it on the next visit.
One note on gas, where the advice is the reverse. Do not shut a gas valve yourself in a suspected leak. Get out, and let 911 and the utility handle it.
Finding it is half the job, and fixing it right is the other half
Once we know exactly where the leak is, you get options in writing, with the price on them, before anyone picks up a tool. If a repair will hold and a repipe would be overkill, we will say so. If the line has already failed in three places and the fourth is coming, we will say that too, and we will show you what we saw on the camera or the meter that says it.
We repair and replace water service lines, interior supply piping, drains and waste lines, sewer laterals, and gas piping, and we handle the excavation ourselves when a line under the yard or the driveway is the problem. When we replace a section, we use materials we would put in our own houses.
Wahl is family owned in Pittsburgh since 1980. We are 55 team members and more than 40 trucks working out of an 87,000 square foot facility on six acres in Oakdale. Licensed and insured, master plumber on staff, PA HIC #PA022302, A+ with the BBB, and 1,522 five-star Google reviews at a 4.8 rating. To get a leak found, call us at (412) 276-9245.
Let us reach out to you
Fill out the quick form and we will call you back. For an emergency, call any time at (412) 276-9245.
Questions, answered
Do you have to cut open my walls to find a leak?
Usually not, and that is the whole point of the equipment. Infrared, moisture meters, ultrasonic listening gear, pressure testing and camera inspection let us narrow a leak down before anything gets opened. When an opening is needed, it is one deliberate cut in the right spot rather than exploratory holes across a room. We tell you what we are going to open and why before we open it.
Can you find a leak under a concrete slab?
Yes. Slab leaks are one of the most common reasons people call for detection. A leaking hot line often shows on thermal imaging as a warm track across the floor, and ultrasonic equipment picks up the sound of pressurized water escaping through the concrete. That combination usually gets us to a small area rather than a room.
Who is responsible for the gas line, me or the gas company?
The meter is the dividing line. The utility owns and maintains the main and the service line up to and including the meter. The piping past the meter that feeds your appliances belongs to the house, which means that repair is the homeowner's to schedule. That side is our work, including the permit and the paperwork the utility requires.
Should I shut the water off before you get there?
If water is actively running, yes, shut it off at the main. It stops the damage, and it also sets up the pressure test we use to tell a supply leak from a drain leak. Wahl customers often have a valve tag on that shutoff already. If you are not sure which valve is yours, that is worth asking a technician to show you on a routine visit rather than at two in the morning.
My water bill jumped but I do not see any water. Is that a leak?
It can be. A bill that climbed with no change in habits is one of the more reliable early signs, especially alongside a meter dial that creeps while everything in the house is off. That pattern points to the pressurized supply side. It can also be an outdoor spigot, an irrigation line, or a toilet flapper passing water quietly. Detection tells you which, before you start guessing.
Can you test my gas piping if nothing is wrong and I just want to be sure?
Yes. We leak test existing gas piping, check appliance connections with detection equipment and leak detection solution, and leak test lines again after any repair. That is a scheduled visit, not an emergency call. If you do smell gas, do not schedule anything. Get everyone out and call 911 and the gas utility from outside.
Ready when you are
Call us and get a straight answer. You get the price in writing before the work starts.
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