The first thing is to get something to store our water IN. Start with what you already have, like 2-liter plastic soda pop bottles and/or 2 quart juice jugs with screw-on lids and/or glass canning jars. You can also buy 5-gallon heavy-duty plastic containers (reusable; these usually come with a spout) or mylar storage pouches (in varying sizes -- impermeable to odor, gas and light). Many people invest in 55-gallon drums with a siphon.
Store away from sunlight and strong chemicals (fuels, detergents, pesticides, etc.).Hot water heaters, soft water tanks and the toilet tank (not the bowl :>) can also be used for other (non-drinking) uses. To sterilize, boiling for 5-10 minutes is safest. Iodine tablets have a 3-5 year shelf life (unopened).Consider buying a water purifier.
Please add a comment if you have any other ideas for storing in, and ask a question if you'd like more details about containers, sanitizing, or other info.