Chemical Purification is the most popular form of water purification. Using chemicals is both great for both large quantities and small. Chemical tablets are used frequently by hikers and backpackers to cleanse water for drinking. Typically it takes 30 mins to prepare a quart of water with tablets. Unfortunately these tablets also leave a weird taste to the water. Sometimes it taste like pool water but sometimes it tastes like Iodine. Luckily there are also tablets that remove the chlorine or iodine taste. These tablets unfortunately also require about 30 mins. per quart to work. These tablets can be bought at just about any sporting goods store, and of course Walmart.