Hi, Terry sent me here to ask the group.

We have a new home...only 7 yres old.
The gas water heater is the same age.

one about every 6 months or so...we have a very odd thing happen

we get periodic bursts of black(not brown) water from the hot water lines.

if we turn the tub on hot so we get a thick stream of water...you can see a black horizonal line about 1/8-1/4" thick every now and again.

if i drain the tank fully and let it refill...the problem goes away for another 6 months or so...this is the 3rd time it has happened.

Also...the water doesnt smell funny or anything. we even filled the bathtub up to see if it would stink... it didnt. although the water was a light grey color by the time it finished filling.

any ideas?