Clinical Chemistry Lecture (CCLEC) Fundamentals Practice Test

Distillation removes many impurities by turning water into vapor and then condensing it back to liquid, leaving behind nonvolatile contaminants. Because most organic contaminants are not carried over with the steam, the resulting distillate is very low in organics and is expected to be free of organic contaminants. This is the primary reason distillation is used to produce water that is highly pure in terms of organic content.

Other water grades exist for different analytical needs. Reagent grade water is purified for general chemistry work and may still have trace organics. Special reagent water is cleaner and used for procedures that require lower levels of organics. Clinical laboratory reagent water (CLRW) refers to a set of standards used in clinical labs, with specific classifications for purity that can be more stringent than general reagent grades. The description in the question fits distilled water, which is defined by purification through distillation and the expectation of being free of organic contaminants.