Yes, I drink, cook, shower with my water tank supply. I get my water from a safe shore supply. But here are a few things that I have done or currently do to ensure my water is safe.
Water tank treatment (Peggy Hill)
Turn water heater off at the breaker before beginning. Do not turn it on again until entire recommissioning is complete.
1. Prepare a chlorine solution using one gallon of water and 1/2 cup Clorox or Purex household bleach (5% sodium Hypochlorine solution ). With tank empty, pour chlorine solution into tank. Use one gallon of solution for each 5 gallons of tank capacity, which results in 4 Ounces of bleach for 10 gallons of water.
2. Complete filling of tank with fresh water. Turn on every faucet and allow water to run until what's coming out smells strongly of bleach.
3. Turn off faucets--but do NOT turn off the pump...it must remain on to keep the system pressurized so that the solution remains in the lines. Allow to stand for at least 3 hours, but no longer than 24 hours.
4. Drain the tank through every faucet.
5. Refill tank with clean fresh water and drain again through every faucet.
6. To remove excess chlorine taste or odor which might remain, prepare a solution of one quart white vinegar to five gallons water and allow this solution to agitate in tank for several days by vehicle motion (iow, go sailing and tack a lot).
7. Drain tank again through every faucet, and refill with potable water.
How to Purify Water amount of bleach per gallon