This powerful system purifies both treated water and untreated raw water from such sources as remote lakes, streams, stagnant ponds and water supplies in foreign countries, where regulations may be substandard at best. Perfect for outdoor activities and a must in hostile environments where electricity, water pressure or treated water may not be available. The Crown Berkey® system removes viruses, pathogenic bacteria, cysts and parasites and extracts harmful chemicals such as herbicides, pesticides, VOCs, organic solvents and trihalomethanes. It also reduces unhealthy heavy metals such as lead and mercury. This system is so powerful it can remove food coloring from water without removing the beneficial minerals your body needs. Virtually no other system can duplicate this performance.