Spring sater is ground-water that comes from surface springs, rather than coming from underground springs. It may have some minerals in it, but not enough to give it a taste that make people think of it as mineral water. It is usually very clear water, but some may be reddish.
The use of the term implies that the water sprung to the surface of its own volition, rather than being pumped up. Generally, it comes to the surface by the force of the water, the underground source for which is uphill from where it comes out. The natural pressure of gravity which pulls it downhill also causes it to come out of the spring on its own. The water collects inside the bottom of the hill in a pool called an “aquifer”, and then because the aquifer gets full, the water is forced out.
Some bottled water, while not claiming in text to be Spring Water, may have a picture of a spring in bucolic surroundings to let you infer that it is, if you want to.
The American Food and Drug Administration (FDA) says, though, that anything labelled with the words “spring water” must come from a spring (though they allow you to artificially tap the spring at a spot other than where the water would naturally come up, provided that water will be exactly the same as that which comes out elsewhere naturally), and cannot have minerals removed from it, or added. The water can be disinfected and filtered.
Springs may vary in their output by time of year, and can diminish in capacity if the aquifer is artificially tapped elsewhere with wells.
In consumers’ minds, Spring Water implies clean and pure, but springs, like wells, can get infected by chemicals or pathogens. Bacteria don’t die just because they pass underground. Spring water can be contaminated if it passes through contaminated areas on its way downhill.
A concentrated spring is when the water emerges from a few points, and is intercepted underground before it reaches the surface. This type of spring is less susceptible to contamination.
A seepage spring is when the water seeps out in the soil over a large area. The water is channelled from various points in the area to a collection area, from which it can be obtained for use. It is more susceptible to contamination.
Springs are categorized based on how much water comes out of them. The categories range from 1st magnitude, for the most active, to 0 magnitude, for defunct springs. 1st magnitude springs will produce over 64 1/2 million gallons (244,159,061 litres) per day.
Spring harnessing allows water overflow on purpose, even though you may see it as wasting water, because if the water were allowed to build up, it would move up into soil closer to the surface where it could allow contamination to seep into all the water.