What tool is commonly used to measure the water pressure within a system?

A manometer is the appropriate tool for measuring water pressure within a system. It operates by balancing the weight of a fluid column against the pressure being measured, allowing for accurate readings of pressure in various units. This tool can be essential for diagnosing issues in water systems, ensuring they operate within the desired pressure range.

A hydrometer is designed to measure the specific gravity of liquids, particularly in applications such as determining the concentration of solutions, rather than measuring pressure. A piezometer, while also used to measure pressure, is more specific to measuring the pressure of groundwater and is typically employed in geotechnical and hydrogeological applications. A flow meter measures the flow rate of fluid in a system instead of pressure, which is a different parameter altogether. Each tool serves a distinct purpose, making the manometer the correct choice for measuring water pressure.