Glossary

parts per million

Unit expressing the part of a whole number in units of 1/1000000. Abbreviated to ppm.

Related terms

carbonate hardness
Measure of the alkalinity of water as dictated by the presence of bicarbonate and carbonate ions. Usually expressed as parts per million, milligrams per litre, or degrees (dKH) of which 1 dKH corresponds to 17.848 ppm. Sometimes used a synonym for, but not equivalent to, temporary hardness.
dissolved oxygen
The concentration of oxygen dissolved in a water body. Normally expressed in milligrams per liter, parts per million, or percentage saturation.
total dissolved solids
Measure of the total concentration of both organic and inorganic, microscopic particles suspended in a given liquid. Usually applied only to freshwater systems and measured using a conductivity or total dissolved solids meter with results expressed in units of mg per unit volume of water (e.g., mg/L) or parts per million (ppm). Soft water with low pH generally has low levels of total dissolved solids whereas harder water with higher pH tends to contain correspondingly increased concentrations. Often abbreviated to TDS.