Groundwater originates from various sources and is a crucial component of the hydrological cycle. Groundwater is  water, which originates from the infiltration of fluids through the soil profile and accumulates below the earth's surface in a porous layer. Porosity is the percentage of open void space in the subsurface material. It is expressed as a percent.  Permeability is how readily a fluid can flow through a material. Often referred to as "connected pore space".  Piezometric surface is the surface in which water is pushed up to by the pressure below Spring is where water flows out without the aid of pumping. It may be caused by hydrostatic pressure (pressure pushing upward), or the intersection of the piezometric surface with the ground surface. Also referred to as an Artesian System. An aquifer is the porous unit or layer of rock that is able to store or hold water and transmit enough fluid to be of economic value. An aquitards is rock material that do not contain water but allows water to pass through it. Fluid flow is not good and the unit may often be termed a "cap rock", not allowing underlying water to flow upward. Different types of water that contribute to groundwater is described as:

1. METEORIC WATER

                                                

   • This is the primary source of groundwater. It originates from precipitation such as rain and snow.
   • When rain falls, some of it infiltrates into the soil and percolates downward through pore spaces and fractures in rocks until it reaches the water table.
   • Water from tanks, lakes, rivers and seas is again received by earth after vaporisation.
   • Water is received by melting of snow or rain, hence it is called ‘meteoric’ or ‘shooting star water’.
   • From the surface of the earth, this water infiltrates down below through rock joints, pores and fissures of rocks and is stored at the level of impermeable rocks in the form of groundwater.
   • Another way in which the groundwater may be derived directly from atmospheric moisture is condensation of water vapour from air circulating through the pores and interstices. This is also known as ‘condensational water’ and is the basic source of replenishment in the arid and semi-arid areas.
   • During summers, the land is warmer than the air in the soil. This results in a difference of pressure between the water vapour in the atmosphere and the soil.
   •  The water vapour from the atmosphere penetrates into the rocks as the temperature of the water vapour drops in the cooler soil. A certain amount of water may accumulate this way.
   • A third source is effluent seepage from lakes, rivers, oceans and also man- made channels, but the importance of this varies with the climate of the area concerned. In fact, in humid regions, the groundwater contributes to stream flow by means of effluent seepage, and the gradient of this saturated groundwater more often than not slopes towards the surface water bodies and the oceans.

2. MAGMATIC WATER

                                                                            

   • Magmatic water originates from the Earth's mantle and is released during volcanic activity.
   • Volcanic eruptions can lead to the formation of fractures and fissures in the surrounding rocks, allowing magmatic water to seep into the ground and become part of the groundwater system.
   • This water can have distinct chemical compositions due to its interaction with the surrounding rocks and minerals.
   • Hot magma enters rocks due to volcanic action after which its vapour drops are condensed and converted into water. This is called magmatic water. Apart from it, other sources are those in which groundwater becomes again available on the surface of the earth. They are mainly springs, wells, and geysers. Such water is considered to have been generated in the interior of the earth. It has consequently travelled to the upper layers of the earth’s surface for the first time; this is also known as magmatic water.
     

3. CONNATE WATER

   • Connate water is ancient seawater trapped within sedimentary rocks during their formation.
   • Over millions of years, as sediments accumulate and undergo compaction, the seawater becomes trapped within the pores and spaces between sediment grains.
   • This water is often saline or brackish and can be found at great depths within the Earth's crust.
   • Connate water can sometimes be brought to the surface through processes like drilling for oil or natural gas.
   • Connate water is usually found deep down in the lower layers of the zone of saturation. 
     

Each type of water contributes differently to groundwater characteristics and availability. Meteoric water is the most significant source, replenished regularly through precipitation. Magmatic water, while less common, can influence local groundwater chemistry. Connate water, although relatively inaccessible, can still play a role in certain geological formations and processes.