Detect or find gas leaks in natural gas or LP gas / propane piping, fittings, & appliances:

This article describes how to find gas leaks on LP or natural gas piping, regulators, or appliances, and it provides free sample draft home inspection report language for reporting defects in oil and gas piping at residential properties.

This article series provides descriptions and photographs of unsafe gas piping, indications of unsafe or improperly operating gas appliances, gas meters, and other gas installation defects are provided.

How to Test or Look for LP Gas System Leaks

These questions & answers about tools & procedures used to test gas piping and fittings for leaks were posted originally at GAS LEAK DETECTION, LP / NG - you will want to see the guidance there.

Watch out:  improper installation and even improper inspection and testing methods involving natural or "LP" gas can involve dangerous conditions and risk fire or explosion.

If you smell gas you should leave the building immediately and should do so without doing anything that could create a spark such as operating a light switch or telephone.

On 2017-10-17 by (mod) - gas company locked up our gas meter

This indeed sounds really annoying, I agree. The gas company is locking out the meter because they think the system the gas system unsafe. Nothing in your message tells us what the gas company found and is worried about, though presumably it's a gas leak.

It is possible to pressure test a piping system that is not in use, something your plumber could do. But what I would do at this point is call the gas company to ask them how they want you to proceed.

On 2017-10-17 by Adam

So the gas company won't turn the gas on, and put a bolt in it. Then my plumber says he can't detect the gas if it's turned off, and he can't turn it on. I am clueless on what to do.

On 2017-08-29 by (mod) -

Glad to assist, working together helps us both. Stay safe.

On 2017-08-28 by Anonymous

thanks alot your recommendation helped me alot.

On 2017-08-25 by (mod) - start by turning the gas valve off between the meter and the building.

Sania,

I would start by turning the gas valve off between the meter and the building.

By completely isolating all of the building gas piping, you can watch the meter and if it continues to run then you know there is actually a gas leak at the meter itself. That would be a reason to ask for help from your gas company.

If there is no gas usage when the main valve is turned off, and usage resumes when the main gas valve is turned on, then there is a leak to be found in the building piping, valves, or in one of the appliances.

At that pointI would follow the gas line from the meter onwards, and one by one check off every length of piping and every connector to each shut off valve.

You may need to use a more accurate gas leak detector or detection method.

For example, I have found that soap testing, while traditional and a perfectly good gas leak testing method, can be difficult to perform with complete accuracy.

For example there can be a leak in an area where the soap bubbles simply are extremely difficult to see such as on the backside of a connector that is close to a wall.

That's when other gas leak detection instruments can be quite helpful.

Your gas supply company may be able and willing to help you by sending a technician who has better equipment. Try that and let me know what you are

On 2017-08-25 by Sania afzal - meter is showing reading.

While all the cocks of gas are off but still the meter is showing reading. We have check all points with soap aolution they are not liking is it possible that whole internal house fittings in cements could be liked if then whats a solution. Plz tell me

On 2017-03-02 by (mod) -

Mom

I don't quite follow what's happening from your brief text, but I suspect that your gas company thought that there was a gas leak somewhere inside your home, and to prevent blowing up the home they shut off your gas supply, perhaps also removing their meter at the same time.

Call your gas company to ask for an explanation.

Watch out: if you smell gas do not do anything that could cause a spark or flame as that can cause a fatal explosion: get everyone to leave the home and call emergency services from a distant, safe location.

On 2017-03-02 by Mommy

Can the meter reader say there's a gas leak in the house when you don't smell it.you come home and find entire meter gone?

On 2016-12-21 by (mod) -

Nepomucen said:
Great artistic photography

On 2016-12-11 17:25:16.058909 by (mod) -

your gas company will of course use their own sensitive test equipment to check for other gas leaks before they decide but the system is safe.

On 2016-12-11 12:20:16.574815 by Nelson

I live in a condo building with 21 separate natural gas metered lines, one for each condo plus the building.

After smelling gas in the garage, the gas company found leaks in two of the 21 lines and proceeded to turn off the gas to the entire building. After the leaks are repaired, what test procedures should be followed before the gas can be turned back on? The system has shutoff valves for each metered line.

On 2016-11-23 18:54:00.644100 by (mod) -

Jesse, you're asking a legal question of a technical guy who's not a lawyer.

In my experience very small leaks at the shutoff valves on LP tanks are quite common and might even be appreciated by the gas companies as long as the leak is both outdoors and small enough as to avoid a fire or explosion. In some communities an owner has probably to make a fuss to get a gas company to find and fix such leaks.

The technical issues: you need to find and fix gas leaks promptly for safety.

The legal question of who pays for lost gas fuel or other losses, assuming the total cost is big enough to be worth the heartache, expense, and delays, is one to discuss with your attorney, with your lease contract in-hand.

On 2016-11-23 18:11:31.314044 by Jesse.

If a service tech comes and inserts a t connector to be able to switch between two lp tanks, one leased and one owned and does not test the valve on the leased tank while it was in the closed position( or on position either) and it causes a loss of lp from the private tank who is liable for the lost fuel?

The owned tank is proven sound and leak free, it is clearly the leased tank valve that caused the loss.

On 2016-06-11 20:51:10.066049 by (mod) -

good question, Gene.

The tech is "sort of" right. I have confirmed by field test and by speaking with other inspectors and plumbers that a *small* gas leak at the gas control/valve on gas-fueled water heaters is so common that I'm cautious about calling it out. We have replaced a valve only to find the very same leak at the new one.

We also get a response from the TIF8800 from pipe dope and other solvents that might be used at the water heater piping connections.

But in my opinion you should never be able to smell the propane from those tiny nuisance leaks, and the TIF won't detect them from even 6-12" away.

If you smell propane near the water heater there's a leak that might be more dangerous for several reasons:

- the gas may accumulate to a level that's explosive

- even if the only detectable leak point is the case seam on the gas control, the leak seems larger than common and risks a worsening and thus dangerous condition.

I'd warn the homeowner of at the very least a potentially dangerous situation with the caveat that in general if you can smell propane indoors there's a hazard.

On 2016-06-11 19:01:42.886905 by Gene

I am a home inspector using a Tif 8800, I detected a leak (propane)at a gas valve on a water heater, detector was set at a slow tick, when I found the leak the detector screamed and all six lights lit up. The technician told the home owner this is normal for this valve. Is this right?

You could smell the propane when you got close to the water heater

On 2015-11-13 23:10:57.148704 by Nathan

Best way to pressure check natural gas line from inlet to appliance

On 2015-10-02 14:32:40.708465 by Gerri

Can a gas pressure test show a quick drop if the pilot lights on the stove have been turned off? Wondering if air is escaping through those openings.

On 2015-09-26 16:42:07.255578 by (mod) -

Gas leak calculation:

See the bottom of the article above where we repeat your question and provide a detailed answer.

On 2015-09-26 12:05:36.085898 by I had a 1mm sq hole ina domestic Gas pipe that went undetected for 4 years if on average the gas heating was on for 1 hour every day how much gas would i have lost at 1/4PSI

I had a 1mm sq hole in a domestic Gas pipe that went undetected for 4 years if on average the gas heating was on for 1 hour every day how much gas would i have lost at 1/4PSI

Question:

(Oct 24, 2014) cyndi said:
The gas company said there must be leaking gas pipes in the ceiling because it won't hold pressure.

Do you know how the plumbers I hired to fix the issue will be able to know which pipes to fix so they dont break my ceiling and replace every pipe when it could just be one pipe? not sure how it works

Reply:

(Nov 15, 2014) finding a leak said:
If the plumbers do not know a gas pipe from a water line then you definitely have the wrong plumbers.

Gas lines that are supply lines should be black iron with threaded fittings. There should never be galvanized lines for gas.

The gas will dissolve the oil in the galvanizing. If the ceiling is drywall and not readily accessible, the plumbers should make sure the leak is not in an exposed line first before tearing out ceiling. It may just be a flare nut that needs tightening or a leaky regulator on an appliance.

The only thing you can do is hire people that are know to have a good reputation and not Joe Blow that is an expert on everything.

Ask for references. For myself, I can give a homeowner the names of many many people I have worked for. If they cannot do that, tell them to have a nice day: you think you want to check some more.

Question:

(Jan 14, 2015) Anonymous said:
Help! We smell gas and gas company came out and confirmed there was a leak in system.

They didn't identify where but they turned off gas valve and said to have a heating professional find & fix it. TWO visits by plumber and heating specialist failed to find a leak with both a pressure test and a gas meter.

However we still smell gas in the heater area but it appears to be intermittent. Is this possible? I'm concerned about the safety of my family. Should we be in the home? What steps can we take?

Reply:

Sounds as if you need to get the gas company back to perform more testing using combustible gas analyzers not just a pressure test. How those instruments are used and how carefully and how thoroughly makes a lot of difference in reliability of the result.

Intermittent odors could be due to intermittent leaks such as when equipment operates, or due to variations in building ventilation when a leak is constant.

Very small trace leaks do not necessarily cause an explosion but NO gas leak should go unrepaired. The risks are too serious.

Question: how can I fix a leak in an old lever type gas shutoff valve?

(July 22, 2015) Steve Kohan said:
I have a gas leak at the shutoff valve were the knob enters the pipe. How do I fix this small leak on a old lever type shutoff valve?

Reply:

Unless the gas leak is due to an improperly-tightened fitting or a poorly-made flange on gas piping that can be corrected, you'll have to replace the valve. Sorry. NO external fix such as a patch, tape, or goop would be safe.

Question: repair a line breakage a foot from tank at the bottom

(Sept 11, 2015) Tim said:
can you repair a line breakage a foot from tank at the bottom, right before it goes into the ground, without replacing whole line that goes to the house?

Reply:

Tim:

What are we discussing here? A leak in a tank, in gas piping, or in some other type of piping.

Any piping or gas line can be repaired using proper fittings and safety measures (like turning off the gas supply and testing the repair for leaks), but the question of how much line needs replacement should be decided *after* an assessment of the condition of the rest of the piping; if it's deteriorated it's unsafe and thence patching an immediate leak is inadequate and also unsafe.

On 2013-02-26 by Daniel

Are propane drains required in basement heater / utility closets.

On 2012-10-20 by Steve Harper

I have a gas leak in my trailer (propane). I took it back to the dealer, who said they could find nothing.After going through 7 tanks in a season, with most of the cooking on a separate BBQ, something is wrong.

If I shut the tank off for a couple of days then turn it on, you can hear a gush of gas coming from the tank; re-filling the plumbing. This tells me there is a leak. I plan on putting on a new tank, and weighing it. Turn on the valve when I am not using the trailer, and weigh that tank daily.

A continued weight drop with the trailer not being used at all will be a clear indicator of a leak. Does this sound reasonable?

On 2012-06-14 by (mod) -

Kenneth followup:

Kenneth we have not found a recommended replacement age for gas piping, and if there were to be one developed it would have to consider variations in pipe material. Black iron pipe is often in use for more than 50 years.

On 2012-06-14 by (mod) - gas leak detection soap solution formula

Anon sorry you find soap solution a mystery. Soap solution is simply a few drops of liquid detergent into a small bottle of water. The proportions are not critical except you need enough soap in the water to allow the solution to form a bubble

. If you can shake the bottle of soap solution and see a froth of bubbles, it's soapy enough.

We are dedicated to making our information as accurate, complete, useful, and unbiased as possible: we very much welcome critique, questions, or content suggestions for our web articles. Working together and exchanging information makes us better informed than any individual can be working alone.

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On 2012-06-12 by Anonymous

no formula for soap solution, useless

On 2012-04-16 by (mod) -

Kenneth I don't know and will research further

On 2012-04-16 by (mod) -

Anon, temperature change may be a factor but of course you must be dead certain there are no leaks, absolutely. Even a small leak can accumulate and be unsafe.

On 2012-04-15 by kenneth

I have a gas piping system installed at my small restaurant, the materials used for the pipes were schedule 40 BI pipes and the installation is about 5 years now, I have checked the system for leaks, but so far, I didn't find any leaks on the system.

Is there a provision in the NFPA code that states about how long should I consider replacing the piping system?

On 2012-02-29 by Anonymous

I ran all new black iron pipe in my house for a remodel. I pumped 100 psi in the pipes and had a couple of small leaks. I fix those, but still get a 10 pound drop over night. Since the natural gas pressure is so low should I worry?

On 2011-10-05 19:57:44.148852 by (mod) -

Polly,

First you'll want to have an expert trace the odor to its apparent source. Gas like odors may be from an LP or natural gas supply - most people can recognize the odor of the mercapatan odorant placed in gas supplies but not everyone.

Second you'll want to rule out other gas odors such as a backing up sewer line, dead animal, garbage, etc.

Third: wind or other conditions can make tracking down a gas leak tricky, and unfortunately I've found that the expertise of gas company field people varies from really expert to inept. But the gas company has a huge interest in avoiding a catastrophe.

Both independent inspectors and gas company employees should be equipped with gas leak detection instruments (not just a cigarette lighter, nose, or soap solution) that can help pinpoint the presence of a leak.

keep us posted.

On 2011-10-05 by Polly J.

I have had intermittent gas smell near the front door of my house over the past ten years or more. The gas meter is halfway around the house from the front door. The gas company has been out here on four occasions and has found no leak. T

oday, my plumber again mentioned the odor and suggested that it may signal a danger. What to do if the gas company is again unable to find a leak???? Thanks.

On 2011-09-14 by (mod) - can you check on leaks or pressure if the GAS HAS BEEN TURNED OFF

Eric
To inspect gas piping for leaks when gas service has ben turned off one would begin with a visual inspection of the piping and connections, but that process alone would be inadequate. The gas piping system will need to be tested under pressure, using air or an inert tracer gas.

Monitor for a pressure drop when using air; use a tracer gas such as used in HVAC testing. Test pressures? We will need to check the AGA specifications on leak testing.

On 2011-09-14 by Eric Clifton

How can you check on leaks or pressure if the GAS HAS BEEN TURNED OFF

On 2011-08-23 by ret

thank you very informative

...

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