We can carry 120 liters of water. We have two taps, one for regular water and one for filtered water; we use a Nature Pure water filter. We never buy bottles of water, but always tank water that the locals drink and drink it filtered. In nearly three years of travel through Middle East, Africa, South America we never had a stomach disease. A cartridge costs about € 90; we use one in about six months, the sign for replacement has been that the water flow became too slow. Avoid using water with sand in it, that clutters the filter very quickly.