presence of bicarbonates of calcium and magnesium

silt or suspended matters picked up in a surface; discoloration and bad taste; filtration

over 300mg/L; 17+

iron and manganese; discoloration of fixtures and laundry; precipitation by filtration through manganese zeolite oxidizing filter

slightly hard

presence of noncarbonic salts (sulfates, chlorides, and nitrates)

very hard

calcium and magnesium; clogging, burning out of boilers, laundry and food preparation; ion exchanger and zeolite process

76-150mg/L; 4 to 8.5

acidity, entrained oxygen and carbon dioxide (low ph); closing of iron pipe rust, destroy brass pipe; raising the alkaline content

build up of minerals and rust from inner linings of pipes; caused by minerals like calcium carbonate and magnesium

organic matter; unpleasantness; filtration through activated carbon purifier filtration

other method for hard water treatment

standard ion exchange water softener; hard water treatment; the hardness (calcium and magnesium) is replaced with sodium

soft

carbon dioxide, containing decaying vegetation; corrosion, rusting, and clogging of steep pipes; through a bed of crushed marble or limestone, sodium silicate

151-300mg/L; 8.5 to 17

sum of the calcium and magnesium concentrations; combination of temporary (carbonate hardness) and permanent (non-carbonate hardness)

measure of total calcium, magnesium, iron, and other metallic elements that contribute to the “hard” feel of water

0-75mg/L; 0 to 4

moderately hard

hard

contamination by organic matter or sewage; disease; chlorination by sodium hypochlorite or chlorine gas