It is recommended that you thoroughly sanitize the water system upon delivery, following long periods of non-use, and after any suspected contamination. There are various commercial solutions approved for RV use available that will assist you in completely sanitizing the water system.
Prepare a chlorine solution using 1 ½ cup of household bleach (5% sodium hypochlorite solution) per 100-gallon tank of water. This solution can be funneled into an empty garden hose and forced into the tank by water pressure. Repeat as needed.
Complete filling the tank with freshwater. Open all faucets to release air. Pressurize the system until the water flows. Turn off the pump.
Allow the solution to stand for three hours.
Drain and flush the tank with potable freshwater.
To remove excessive chlorine taste and odor which may remain, prepare a solution of one-quart vinegar to five gallons water and allow the solution to agitate in the tank by vehicle motion (several days if possible). The same method of installing bleach can be utilized to install the vinegar solution.
Drain the tank and again flush with potable freshwater.