[JRTJH]

Oak,

To answer your question about quantity of water needed to flush, sanitize and prep your trailer for travel. 250 gallons is probably twice what you'll need.

To do the "de-winterization" you'll need to connect a hose to the city water port (if you have pressure) or fill the fresh water tank and use the onboard water pump. Run city water (or the water pump) and flush all the antifreeze from each faucet (leave the water heater empty and bypassed). Once the water runs clear at each faucet (hot and cold) then add 1/4 cup of Clorox per 15 gallons of water to the fresh water tank. Install the anode rod in your water heater and turn the bypass to allow the water heater to fill with "Clorox water". Once that is done, start with the faucet nearest the water pump and run the COLD faucet until you smell Clorox. Then run the HOT faucet until it stops sputtering and you smell Clorox. Move to the next faucet, repeat until all the faucets are purged with Clorox water. Don't forget the outside shower and the toilet.

Let the trailer sit overnight with Clorox in all the lines. Then, drain the fresh water tank, refill with fresh water, drain the water heater. Turn on the water pump, allow it to run until the water heater is full, then repeat the "faucet flush" until each runs clear with no Clorox smell. After that, you're essentially done with de-winterizing and sanitizing the water system.

At that point, you can refill the fresh water tank if you're traveling with a full tank or adjust to the level you want for traveling.

All the above shouldn't take much more than 100-150 gallons for a 43 gallon FW tank. You could probably "get by" on 86 gallons if you wanted, 43 to fill/sanitize and 43 to flush the system.