Total dissolved minerals in rainwater are typically:

Rainwater typically has low total dissolved minerals, which results in very soft water. This is because rainwater originates from the condensation of atmospheric water vapor, which is distilled water and generally free from dissolved solids. As the rain falls, it may pick up some impurities from the atmosphere, but the overall concentration of minerals remains low compared to surface waters or groundwater sources.

Given that rainwater has not yet interacted significantly with soil or rock that can leach minerals, its mineral content is minimal. This is why it is classified as soft water. The softness of rainwater makes it suitable for various applications, including drinking, irrigation, and other uses where low mineral content is advantageous.

In contrast to rainwater, other sources of water, such as groundwater or water that flows through mineral-rich rocks, tend to have higher dissolved mineral content, leading to classifications like hard water.