Spring supplies are therefore a source of groundwater, which in most instances has fewer micro-organisms (e.g. coliform bacteria and protozoa such as Giardia and Cryptosporidium) and chemical contaminants than a supply from surface water.
The point at which the groundwater reaches the surface is prone to contamination, so must be protected using a structure called a spring box.
This is often surrounded by a fence to keep animals out, with other common features being a ditch on the uphill side, an overflow pipe and a well fitting lid.
The method for doing this will vary according to the contaminant, but can include sand filters, pH balancing units and ultraviolet light.
[1] In the United Kingdom, over half a million people live or work in a premises that relies on a private water supply such as a spring.