Use the Potassium iodide tablets to treat water that has been potentially contaminated with radiation. It works by saturating the thyroid with stable iodine so that radioactive iodine isotopes aren’t needed and thus aren’t absorbed by the body. Stocking a water filter is a fantastic way to remove the majority of common micro-organisms and chemicals.
Many of these pathogens cause dysentery, an illness you may associate with developing countries due to their lack of access to clean, safe water. It is recommended that each person has access to a minimum of one gallon or 4 liters of water per day.
This gives you 2 quarts for drinking and 2 quarts for sanitation and food preparation. Keep in mind that you will always need more water than you think, be it to clean dishes, reconstitute dried foods, maintaining good hygiene and of course, keeping hydrated. So it is important to have more than one method of producing safe, clean water.