Every so often - once, maybe twice a day (and more if we're running hot water for dishes, laundry, etc.) - our water heater makes a click noise followed by a loud rumbling above it. These clicks are fairly common, I think, and I've read that the rumbling is caused by steam and sediment buildup. What I'm wondering is whether the rumbling is dangerous. It seems that it's gotten worse (slightly longer and definitely louder) over the past month or so.
The heater has been there a little over two years, and has never been flushed. The apartment complex is poorly designed, and there really isn't a good way to drain the heater without running a very long hose outside of the building. (Also, doing this would involve shutting off water to the whole complex.)
I wonder if there is any way to tell whether the rumbling is caused by sediment in the heater, sediment in the pipes, or a pipe coming loose from its anchorage, and what the best way to diagnose and repair this problem might be.
Thanks so much for any insight and assistance!