half power and no hot water
First I would say that it sounds like something is seriously wrong with your home wiring. Personally, I would trip every breaker associated with a circuit where the voltage is reading low, including the 220V circuits. 

What I would guess is happening is that maybe the neutral wire on one of your mains lines is broken or loose/disconnected. If that's the case, then all of the power for your electric items is having to go through ground. 

Seriously, flip those breakers and call an electrician. It's probably an easy fix - just reconnect the wire, but if all of your electric power is relying on ground connections, then there's a chance that things that are supposed to be safe may not be - the case of the breaker panel, the case of the washer/dryer, etc. 

It sounds like a voltage divider - hot to "neutral" is not getting 100% of the voltage (power) you're expecting, so "neutral" to something else (ground) is getting the remainder of the power you're expecting. This power is either on its way to starting a fire somewhere in your house, or it's being dumped to ground and is heating up wherever the ground (or water pipe!) is making contact with the ground. 

When you measure voltage, how are you doing it? Hot to neutral? What happens if you go to the breaker box and measure hot to neutral, then hot to ground?