When filling with water, most of it dumps out the side.

I also use a dedicated short piece of hose to fill the fresh water tank. I have a spray bottle close at hand that is filled with diluted bleach solution. I also have a supply of wet wipes. I will spray and/or wipe down the end of the hose before using it.

I also use the wet wipes and bleach bottle for sanitation when I’m dumping tanks,.