Question about the water heater and furnace in my apartment?

I noticed that my electrical usage seems absurdly high over the last couple of months (since I moved in). I'm trying to figure out why it is so high. One thing that I noticed is that there are three hot water out pipes coming from my hot water heater. Only one has a meter on it. Does that mean that my hot water heater is providing hot water for other units? If this is the case, does that mean I am paying the electricity to heat the water for other people? Is this legal? I wasn't informed of it and did not see anything to that effect in the lease.

I can hear clicks and water moving around in the heater even when I'm not running any water. (The hot water heater is in my bedroom closet, so obviously I don't hear it when I'm running my own water... but maybe some older water heaters cycle water through?)

I also kept my furnace on at 55 degrees this month. I have zone heating (last month, I kept it on only in my bedroom). I walked in one day and noticed that the thermostat on my clock said my bedroom was almost 80 degrees. I assume that means that the thermostat is broken. I figure I'm probably still responsible for the electricity (it isn't the power company's fault that the heater stayed on when it didn't need to), but can I ask my landlord for help if it turns out that the high bill was due to a problem with my apartment? I'm not sure.