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.