Taunton Leisure keep a range of different drinking water treatment systems to purify water that may not be drinkable if untreated. A range of chlorine & chlorine dioxide tablets make water safe for drinking, cleaning teeth and washing fruit. Use neutralising tablets to remove the chlorine taste.
There's also the simple amazing Water-to-go bottle, a pocket water purification bottle you can use anywhere to turn pond, stream or rainwater into purified drinkable water. Developed for NASA using nano-technology that filters over 99.9% of all contaminants in water.