The 1% potassium hydroxide solution is a weakly concentrated alkaline solution used in various areas of the laboratory and industry. In microbiology, it can be used to distinguish yeasts and filamentous fungi by soaking samples in the solution and then examining them microscopically, but the effect at this concentration is weaker than with more highly concentrated solutions.

In the chemical industry, the 1% potassium hydroxide solution is used in the production of soaps and detergents, but here it is usually too weakly concentrated and may have to be concentrated. It may also find use in the textile and food industries, especially when a lower alkalinity is desired.

In the laboratory, 1% potash lye may be used as a mild caustic to remove proteins and grease from glassware or to neutralize weak acids. In industry, it can be used in some cases to etch silicon or as an electrolyte, but higher concentrations are usually required. In metallography, the 1% KOH solution can be used to make certain structures in metals visible, but again the effect at this concentration is weaker than with higher concentration solutions.