Which of the following would NOT be used to measure water quality?

Pressure gauges are instruments used to measure the pressure of a liquid or gas. In the context of water systems, they help monitor the pressure within pipes to ensure proper flow and prevent issues such as leaks or bursts. However, they do not provide any information about the quality of the water itself, such as its chemical composition, microbial content, or physical characteristics.

On the other hand, water hardness tests, colorimetric analyses, and contamination assays are specifically designed to assess various aspects of water quality. Water hardness tests indicate the concentration of calcium and magnesium ions, which affect taste and scaling. Colorimetric analyses involve measuring the color intensity of a solution to determine concentrations of specific substances, often used to assess chemical quality. Contamination assays are designed to detect the presence and concentration of harmful microorganisms or chemicals in water, making them critical for safety and health assessments.