A few weeks ago the unit next to mine had the natural gas line to their meter break and it filled my house with gas (the meters for all units are attached to the side of my house). The neighbors got it fixed and I bought myself a handheld Klein Combustible Gas Leak Detector (ET120) so I can more easily check these things in the future.

Over the past week I've been occasionally noticing small whiffs of natural gas when I come home (but not every time). I measured the gas in my home today with the device above and got 2 bars in High Sensitivity mode. Checking by my furnace in the basement gives me 1 bar and the meters outside give 0 bars. Is this something worth calling the gas company over? Or am I just being paranoid.

  • 12
    you should be asking the gas company
    – jsotola
    Feb 9, 2023 at 7:43
  • 7
    I'm reasonably sure the normal level is none. Except for just before you ignite the stove. Feb 9, 2023 at 8:55
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    The only way to answer this question is to read all about "high sensitivity mode" in the widget you bought. Eg after you light a range top there will be a tiny amount of gas in the immediate area. Once that disperses can it still be detected? Sure. Perhaps that mode is to detect very small leaks in pipe joints and not intended to detect safe levels in normal operation? Or not. RTFM :)
    – jay613
    Feb 9, 2023 at 10:38
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    pubs.acs.org/doi/10.1021/acs.est.8b05323 may provide some insight regarding typical and some atypical levels
    – Ecnerwal
    Feb 9, 2023 at 15:08

3 Answers 3


Over the past week I've been occasionally noticing small whiffs of natural gas when I come home

Assuming this means you smell it, CALL THE GAS COMPANY IMMEDIATELY. You should NEVER smell gas in your house (or outside for that matter).

The gas company should have an emergency 24/7 number to call. Get out of your building, call it, and wait outside for the gas company/emergency crew to arrive.

Even if it seems like a small leak, that can mask a situation that can quickly become an explosion-scale leak. Personal anecdote - decades ago we had a gas stove dis- and re-connected. The workers forgot to tighten the gas connection after re-connecting and so we occasionally smelled a bit of gas over the next few days. We finally called the gas company, they discovered the unsecured connection and informed us that if we had accidentally banged into the connection flex tubing, we would likely have had an immediate full-scale gas flow into the kitchen!


I'm going to answer by giving your detector maker some benefit of the doubt, and hope your documentation confirms this.

Some things release gas into the room under normal operation. You want to detect if the amount of gas in the air is more than normal.

If you want to detect or find a tiny leak in a pipe or joint, that would be far less than what is"normal" above. In other words, every time you light the stove top you release (guessing) 100 times as much gas into the room as you would like to detect if you have a small leak. High sensitivity mode is probably for that and normal mode is to detect dangerous levels in a room where small levels are normal.

If I'm right then to detect small leaks you'll need to follow careful procedures that are hopefully in the manual. Roughly: Turn off all gas appliances, air out the room, then seal the room, then wait a little and poke around with high sensitivity.

  • 1
    Respectfully disagree - one should NEVER smell gas at home when not intentionally releasing it.
    – Armand
    Feb 9, 2023 at 21:36
  • @Armand but that is my point ... gas appliances release a small amount of gas when they start up. Intentionally. An over-sensitive detector will alarm constantly. But a detector that ignores these small amounts is useless for detecting small leaks.
    – jay613
    Feb 9, 2023 at 23:16
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    @Armand I disagree and agree. jay613 is right gas appliances will leak (ofc not on their own - only when you start them) a small amount until the spark will ignite the gas creating the flame. but OP says he/she smells it after coming home so if no one cooked in the meantime OP should never smell a gas after coming home.
    – servant0
    Feb 10, 2023 at 1:52

If you can smell it it is already too much.

Since your home was flooded with gas, it can linger for a while in pockets, under the floors and so on.

A total ventilation could help here, thus open all doors and windows for a while.

If it comes back call the gas company.

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