Don't mean to send this thread off-topic, but since you're concerned about radioactive particles in the water, just wanted to point out that eating contaminated food is generally considered the primary route that radioactive particles get into our bodies. This was the experience after Chernobyl. Plants, or animals that eat plants, take up the radioactive isotopes and concentrate them, similar to how mercury becomes concentrated in sea animals as you go up the food chain.

If you really want to be prepared for living with something like Fukushima, then a safe stock of food is certainly a must. And if you check natural or alternative health websites, there are things you can consume that are claimed to bind up the radioactive particles, like certain kinds of edible clays, zeolite powder, certain sea products, etc.