Dry vapor steam cleaners produce a high temperature steam that contains only 5% water. Although some manufacturers will claim their carpet cleaners or carpet extractors are steam cleaners, the technology behind dry vapor steam is quite different. If the unit in question requires a lot of water, it is simply not a steam cleaner and it might result in creating mold and other humidity problems. Actual steam cleaners, such as those from Dupray, will require about 3 liters of water per hour, on average, when used continuously. As the steam contains very little water, it is completely safe for almost every surface, including carpets, upholstery, mattresses, cushions, leather and other delicate fabrics.