May 01, 2018
Hardness. We measured 30 grains of hardness at the office for the month of April.
Average Household Usage: Average household usage was 4,000 gallons for February and March.
Grain per gallon (gpg) is a unit of water hardness defined as 1 grain (64.8 milligrams) of calcium carbonate dissolved in 1 US gallon of water (3.785412 L). It translates into 1 part in about 58,000 parts of water or 17.1 parts per million (ppm).
Calcium and magnesium ions present as sulfates, chlorides, carbonates and bicarbonates cause water to be hard. Water chemists measure water impurities in parts per million (ppm). For understandability, hardness ordinarily is expressed in grains of hardness per gallon of water (gpg).
How many mg/l in 1 grain per gallon? The answer is 14.253768.
1 gallon of water = 8.34 pounds.