Low Pressure Single Meters:

This illustration is of a typical meter facility on a low pressure system, which has operating pressures in the piping on both sides of the meter at about one-quarter pound per square inch. The application is sometimes used for single dwelling homes or small commercial buildings and is usually located outside, in basements or under houses.

A typical shut-off valve can be opened or closed by turning it one-quarter turn, or 90 degrees.