When we turn on the hot water we sometimes get black, greasy blobs in the washer/dryer, bathtub and occasionally the shower. This is disgusting. It is hard to clean off and ruins clothing. The water company said they don't know what causes it. Our water heater is 3 years old; the house is 30 and has copper piping. Can't figure out what is causing this and how to cure it. Any suggestions?

I have no idea. Might be time to call a plumber and have them look at it.