I suspect my natural gas water heater is filling the basement with an off-putting odor similar to what it smells like when someone gets a perm. I guess you could say its like the sulfur/rotten egg smell, but, to me, it's closer to the smell of a perm. Note that the water itself smells and tastes fine.

I've educated myself a bit about water heaters, and found out that depleted sacrificial anodes can cause this odor, but everything I've read talks about the water itself, not the area around the water heater.

The water heater is an AO Smith model, installed in 2011.

What's the deal?

A few more details: It's definitely not the smell of natural gas. Also, our boiler sits next to the water heater. The boiler's pilot light is on and fine. Our thermostat is currently not turning the heat on, so it's just idling. To eliminate it completely as a variable, I turned off the gas to the boiler. That didn't help.

  • Do you have a drain in the basement?
    – Edwin
    Oct 6, 2014 at 19:03
  • Yes. It empties into an old sump pit which is pumped out into the sanitary sewer. I recently installed a dehumidifier which empties into the same pit (continually, with a hose). But that's not where the odor emanates. We also have another sump pit (new; 3 years old) which collects water from drain tile buried in a perimeter where the basement floor meets the basement wall. It's a covered pit.
    – trw
    Oct 6, 2014 at 19:18
  • Check the vent, make sure it has a clear path to the outside and no birds have decided to make a nest in it.
    – diceless
    Oct 6, 2014 at 19:57

1 Answer 1


It turns out it's nothing to do with the water heater. The sump pump's backup battery, which is pretty close to the water heater, exploded inside its container. That's what caused the smell.

  • If this is the answer can you mark as answered?
    – treeNinja
    Oct 7, 2014 at 20:26
  • I intend to do so. However, when you provide the answer to your own question, the SE system requires you to wait two days to accept it. 21 hours to go!
    – trw
    Oct 7, 2014 at 21:05
  • Gotcha sorry, I am still new to all of the rules. My apologies.
    – treeNinja
    Oct 7, 2014 at 21:50

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