Dewinterizing- is Bleach necessary?

you can get a replacement valve cover for the gray tank that has a connection for a standard garden hose

https://www.amazon.com/Camco-Durable-Connection-Connection-39463/dp/B000BQKBP2/ref=sr_1_1?dchild=1&keywords=4%22+rv+drain+cover+with+hose+attachment&qid=1630376645&sr=8-1

use bleach, drain to the gray tank, hook up a hose and drain the water farther away from you drive.  the low amount of bleach will not hurt grass, shrubs, etc.

leave the water heater valves in the bypass position so as not to fill the water heater with 6 gals of bleach water and have to rinse that as well.

We use bleach, then drain and rinse with a similar recipe noted above-we add lemon juice and baking soda to the rinse water to eliminate chlorine taste

Vann

We went 5 years without sanitizing our FW tank, yes, we use it for drinking and never got sick.  Then again we live in Michigan and when we camped then it was in the off season when temps were cooler. 

I don't recommend this, the only reason we went 5 years is because we weren't aware of having to sanitize the tank.  Now we do sanitize, 4oz. bleach in 10 gallons of water, let sit for 4 hours and run through the lines and drain the rest out.  Next step is to use white vinegar and lemon juice concentrate in 5 gallons in FW tank, let sit for a few hours and run all the mixture through the lines as the bleach leaves a nasty taste that I cannot handle.  We use it for drinking and being used to well water we aren't used to bleach taste or smell - if we had city or muni water we would probably be used to that taste/smell.