Assuming you have a 30 gallon tank like the rest of us, about 1/3 cup of plain bleach, no fragrance, is all you need. Put that into a larger container of water to dilute it some then pour that into the tank. Fill the tank and leave it stand for at least three hours. If you can smell the bleach when you run water from the faucet you have enough in it. Be sure to run the water through all of the system to clean that too. Too much bleach is not good for some of the plumbing. Empty and drain the tank at least once to get the bleach out.
Look here on the forum library under plumbing for instructions for sanitizing the water tank.
i have a 1983 HiLo, the fresh water tank seems to be at the front of the trailer, i have looked on all four sides and can seem to find the drain valve, i would appreciate it if someone would let me know where i might find the drain for it
Welcome to the forum. Usually the drain for the fresh water tank is on the forward door side of the trailer. It's a turn valve connected to plastic tubing.
i have a 1983 HiLo, the fresh water tank seems to be at the front of the trailer, i have looked on all four sides and can seem to find the drain valve, i would appreciate it if someone would let me know where i might find the drain for it