The purpose of this document is to review magnetic inductive flowmeter (magmeter) principles of operation, calibration, and selection. The performance and the reliability of these meters with no moving parts will be discussed. The meters require less maintenance and are more accurate than mechanical meters in use today. Magmeters are used in a wide variety of applications including the measurement of wastewater, raw water, treated water, and revenue generation and in different stages of the treatment process such as the measurement of settled water, supernatant water, and backwash water and for proportional chemical addition (pacing). These meters have also been widely used in large-diameter intercity custody transfer pipeline applications.