IMO, there was RV antifreeze, albeit a small amount that seeped into the water heater tank. Been there, done that. Drain the tank, leave drain open, then connect to city water and allow it to flush the tank for a few minutes. Cold water inlet is in bottom of tank so it will flush the bottom, below the drain opening, quite well.
2000 Winnebago Ultimate Freedom USQ40JD
, ISC 8.3 Cummins 350, Spartan MM Chassis. USA 1SG, retired;PPA,Good Sam Life member,FMCA."We the people are the rightful masters of both the Congress and the Courts - not to overthrow the Constitution but to overthrow men who pervert the Constitution. "Abraham Lincoln"