Here's why:

* Percolation: Groundwater forms when rainwater soaks into the ground and moves through the soil and rock layers. This movement is called percolation.

* Dissolved salts: As the water percolates, it dissolves minerals and salts from the surrounding materials. The types and amounts of dissolved salts depend on the rock and soil composition.

* Carrying salts: The groundwater then carries these dissolved salts with it.

Examples:

* Hard water: This type of water contains high levels of dissolved calcium and magnesium, which can cause mineral deposits in pipes and appliances.

* Saltwater intrusion: In coastal areas, saltwater from the ocean can seep into freshwater aquifers, contaminating the groundwater with high levels of dissolved salts.

So, while all water can carry dissolved salts to some degree, the term "groundwater" specifically refers to water that has percolated through the ground and dissolved salts along the way.