Water Heaters - Foamy Hot Water - ???

I just closed on a house that constantly has "foamy" water coming out of all faucets when I run hot water. The water also has a faint, funny smell to it. Again - only when you run the hot water. If I run only cold water, both problems goes away. This leads me to think the problem is isolated to the water heater in some way. It is natural gas heater, and is city water. Spoke to a few neighbors they do not have the same problem.

I should say the house had been vacate and was "winterized" since November. And, of course, none of this come up during home inspections.

Any suggestions/ideas what could be causing these issues?

Thanks in advance for any replies.

Was the water just recently turned back on?
With city water, the air should work itself out.

Water was always on, but the home has been vacant for months. It was "winterized" in November. I think this means that anti-freeze was put in the system.

If it was air in the line, wouldn't I see the same issue when running the cold water?

Thanks.

what does the smell smell like? is it kinds of a rotten egg smell? if so then it is probably in need of a new anode rod. if not and it is because they winterized the water heater then it should be food grade antifreeze so draining the water heater completely and flushing it out the flushing the lines real good should do the trick

If antifreeze was used, normally the water is shut off, the reintroduction of fresh water and flushing of the antifreeze, compounded by the heating releases the oxygen that you are most likely experiencing.