Before we leave we vigorously shake/rinse the containers with a 1-4 solution of water-bleach then do the same with tap water. It takes just a couple of cups and about 5 minutes to do it. Then we fill them with fresh tap water before we leave unless it's a commercial, state or national park...
We carry 1 or 2 26L Reliance Aqua Tainer jugs inside the truck. We also carry potable aqua tablets if we aren't sure of the water quality.
REF: Aqua-Tainer - https://relianceoutdoors.com/collections/water-containers/products/aqua-tainer-4g-15l?variant=36996955242660