Because the precipitates interfere with heat transfer, they must be removed. The deposits are generally salts of calcium and magnesium but iron, manganese and many others may be included. Acetic acid is the most common cleaner used in home stills. Any strong acid would work, but acetic acid is much safer than most. Hydrochloric acid, for example, is very aggressive and so must be used with care.
Manufacturers usually recommend a cleaning procedure, product and frequency for their equipment.
Portable units typically have 500 to 700 watt heating elements and produce 3 or 4 gallons per day. The larger units have heating elements of 1,000 to 1,500 watts and produce 8 to 12 gallons per day. The largest units for home use operate on 220 to 240 volt current, have heating elements of 2,500 to 5,000 watts, and produce 20 to 50 gallons per day. Costs vary according to size. Most manufacturers make only one or two basic distillation units.