What type of water is used in an autoclave?

• A. Distilled water
• B. Tap water
• C. Sea water
• D. Mineral water

Answer: (A)

Autoclaves rely on steam under pressure to sterilize, so the water used to generate that steam must be as free of minerals and impurities as possible. Distilled water has most dissolved salts removed, which prevents mineral buildup on the boiler and inside the chamber. When minerals from tap water or other waters scale the surfaces, heat transfer can become inefficient and tiny niches can shield microbes from the steam, reducing sterilization effectiveness. Impurities in water can also leave residues on instruments or react with metals, potentially causing corrosion. Sea water is too salty and corrosive for the equipment. Therefore distilled water is the best choice to maintain steam quality and protect the autoclave and its contents, ensuring reliable sterilization.