Hardness is caused by an accumulation of multi-valent metal cations such as calcium and magnesium. Hardness affects the cleansing ability of water and results in a build-up of scale in water systems. This, in turn, can impair the water delivery system and lead to problems associated with reduced water intake. Nitrates and nitrites in water are considered serious potential hazards. Most nitrate problems are caused by decomposition of organic material and from runoff from heavily fertilized fields.
Nitrates can move rapidly through soil and can caused persistent problems.
Nitrates can react with haemoglobin to reduce the oxygen-carrying capacity of the blood. This can lead to serious problems, especially in human infants. Pigs are tolerant of most nitrate levels in the water, however producers need to be aware of nitrate's hazardous nature, especially how it relates to human health concerns. High sulphate concentrations are a problem often associated with poor well water quality. Sulphates can cause upsets in the gut of the pig which could result in diarrhoea, and possibly reduced performance.