Foamy water from water heater

[Paul Mermelstein]

This is puzzling. Recently we've been getting foamy water thru the faucets but only for hot water. If I by-pass the heater, no problem. Only water coming from the water heater. It does not have any odor. The "foam" seems to be very fine air bubbles. Any ideas?

 

[Don S/V ILLusion]

My guess given your location and time of year - you used something in the system to winterize that left a residual to foam upon aeration

 

[Skipper]

My guess given your location and time of year - you used something in the system to winterize that left a residual to foam upon aeration

Agree.
In any case, just drain the tank and refill. Or, run loads of water through it till the foam stops. Or, ignore it and run water as usual, and it will eventually run clear.

 

[dziedzicmj]

also possibly, your in-tank anode is gone and you are getting corrosion inside the tank (at least the rod around which the magnesium anode is mounted). Do you also get a smell of rotten eggs?