Why are water pipes laid 2-3 meters underground?

All materials are subject to plastic deformation when their surface temperature changes. When heated, all bodies expand; when cooled, they contract. For pipelines, such deformations are undesirable, since they create additional mechanical stress on the joints, which can lead to rupture in these places. In addition, when it freezes, the pipes can burst, since the volume of ice is greater than the volume of water from which it is formed. At a depth of 2-3 m, ice does not form in the ground, and the temperature is not subject to strong fluctuations all year round.