1st off, you could have left out the part about being naked without glasses!
2nd, if you have well water, or live in an older area with old water mains, it could be just rust (pretty harmless). Old electric water heaters sometimes give off a black residue, that I THINK is caused by normal air in heated water...causes some reaction with the copper pipes. (dissimilar metals/galvanic corrosion). So, rust is not a big deal, health wise, but if the stuff is black, I would call a plumber. Eric