X-RAYS: Electromagnetic radiation with a very short wavelength (0.01 to 12 nanometres), shorter than ultraviolet radiation.
YIELD: the amount of product water produced by a water treatment process.
ZEOLITES: Hydrated sodium alumina silicates, either naturally occurring mined products or synthetic product, with ion exchange properties.
ZERO SOFT WATER: Water produced by cation exchange process and measuring less than 1.0 grain per U.S. gallon (17.1 ppm or 17.1 mg/L) as calcium carbonate.
ZONE OF SATURATION: The layer in the ground in which all available interstitial voids, cracks, crevices, holes are filled with water. The level of the top of this zone is the water table.