Dry chemicals can be stored most anywhere, just be sure to seal the containers up tight to keep them dry.
The one to worry a little about is muriatic acid. Bottles you purchase it in are designed to vent fumes so they don't build up in the container. But, that means you'll have some low level MA fumes in the area of the jug most of the time. This can be hard on anything metal in the area, increasing corrosion. Don't store near vehicles, bicycles, tools... etc in the garage. If storing indoors, do not store near furnaces, water heaters, washers, dryers or other household appliances. Again, it increases corrosion. It should be stored in a cool but well-ventilated area away from these types of items. Mine resides in a small pantry area in the utility room, but well away from the appliances in the room during the winter. In the summer it goes in the shaded plastic cabinet in my screen porch.
