I'm looking for ideas on what might cause the very deep hum I hear in my house when it's quiet. It's been present 24/7 for many years. When I'm alone in the house and nothing is turned on it's actually loud enough to be annoying, but it's not loud enough to record on my phone.

I live in a semi-rural residential neighborhood with no industry within miles. I can turn off my main breaker and the noise still present, so I assume it's not coming from inside my house. I'm 2 to 3 miles from an Interstate highway. Most of the time when I'm outside I cannot hear road noise from the highway. We have county water but no natural gas or sewer. It's slightly louder in my basement. It's not louder near where the water pipe enters the house.

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    Are you sure it's not in your head? Well, in your ears really. Tinnitus can be low frequency as well as the more common "ringing" sound. Try some noise cancelling headphones as a test. They will have no effect on tinnitus but will be quite effective against LF background noise. – jwh20 Aug 16 '19 at 23:58
  • maybe there is a secret government research facility under your house ... look for trapdoors in your basement .... seriously, there may be a pipeline running underground .... or there may be a cave system near your house and you may be hearing wind noise from inside the caves – jsotola Aug 17 '19 at 0:28
  • @jwh20 The intensity changes as I move around the house. Also, I have high-frequency tinnitus, I can tell the difference. There are a lot of strange things running around in my head. This noise isn't one of them. :) – Troy Turley Aug 17 '19 at 1:39
  • I was going to say utilities... But what would have made this story better is if you mentioned you have others that notice the exact same thing. Witness accounts account for A LOT. Incidentally, while replacing some plumbing lines in my crawl space beneath my home, I heard a strange hum too. I at first could not figure out where this him was coming from ... I then noted the open "out" main sewet line I had cut to make repairs.. – Retired Electrician Aug 17 '19 at 22:37
  • That's the source... sewer line ! Our sewage treatment plant is 9 miles away... Yes I could hear the plant / pumps running – Retired Electrician Aug 17 '19 at 22:48

It could be the transformer for your house. Do you know where it is? On a pole? In a box on the ground? The noise should be distinctly louder as you get closer.


A few possibilities come to mind.

  • Are there any high voltage power lines nearby, or other buried electrical on your property? Even though you turn off your main breaker, there might be some sort of induced electrical into your house.
  • Even though you're killing the main breaker in the house, is there an outside (or possibly buried) stepdown transformer from your electrical supplier that might be inducing the hum on your feeder lines to the house, or acoustically coming into the basement?
  • Does your main breaker control ALL electrical? Maybe a well pump or radon removal fan that's tapped off before the breaker you're throwing?
  • Any possible battery-powered mechanical fans/clocks/timers that might be making noise even with the power off?

Some possible items that can produce sounds are; transformers for a door bell or furnace, the ballast in a florescent light that is on, a computer and even some TV's. You could turn off the main circuit breaker for the house and if the sound goes away, then it is being produced by some electrical device. If it is an electrical item, then start by turning off each circuit breaker 1 at a time until you find the one that controls the sound.

  • They mentioned in the question that they tried turning off the main breaker already. – user3757614 Aug 17 '19 at 22:26

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