Jean writes from St.Paul, Alberta: "I live in town and have municipal water. I have started getting yellow water from my hot water tank. It is not smelly, but it does have some suspended flakes. I also don't have the same volume of hot water as I previously had; yet it is still very hot. A friend suggested the anode may be gone but a plumber insisted he has never had to change an anode in town. Any idea what could be causing this?"
If the flakes were white and looked like plastic, it could be a defective dip tube. See "degenerating water dip tube".
If there is a lot of corrosion going on you can have a build-up of stuff in the bottom of the tank that effectively reduces the quantity of water left in the tank. This would explain why Jean was getting less hot water. We contacted Jean and asked him to inspect his anode tube himself, simply turning off the power, then unscrewing the anode from the top of the tank.
He was right, it was thoroughly corroded, indicating that it was doing it's job in protecting the tank from something in the water. Replace the anode and flush the tank, and he was back in the shower.