I'm getting a white substance in my faucets and shower head that looks like salt, it collects at the faucet filter and clogs up my shower head. Lime away seems to help unclog the shower head. Any idea what it might be? I was thinking it is calcium from the hot water heater because my neighbors (same building) are not having the problem.

Is the white stuff kind of gritty or does it turn to cream between your fingers? Could be lime but it could also be a dip tube in your water heater. Start flushing your water heater one or twice per year to avoid this problem.

It is gritty, doesn't break down at all. I'll try to flush the WH. Thanks.

Hard stuff is usually a deteriorating dip tube. Flushing the tank may help a bit but there is a lot more tube still inside. You might want to consider replacing the tube or the entire tank if it is long in the tooth.