I usually just use the screw top type you can get in Mexico. See picture below, not screw top, but you can get them at some places in the US and you can find them quite readily in Mexico. It is pretty easy to simply transfer water from any other brand, or if it is the same, just exchange them. Water is available at all OXXO stores which are often attached to Pemex stations. Water is cheap enough that if you are worried about spillage, just dump it out before travel days. I have even seen people filling their fresh water tanks with bottled water. It is not worth trying to purify water. I do put 4 oz of peroxide per 50 gallons in my fresh water tank, just in case I forget & brush my teeth with it, and I put a small amount of bleach in the dish water.
You can buy tippers that fit the standard 5 gallon tanks down there for about $20, You can just chuck it on the bed during transit.
Delivery in RV parks in Mexico is also common.
