There are no legal criteria in Europe for determining the quality of drinking water for livestock. However, the drinking water quality still has to meet specific criteria since animal products intended for human consumption are subject to specific requirements as well. The safety of water is assessed based on bacteriological criteria (total bacterial count and the number of coliform bacteria) and chemical parameters.
The table below summarises the interpretation of water quality parameters according to GD Deventer in the Netherlands.
Source: GD Animal Health (Netherlands)
* The values in the 'good' columns represent no negative effects for the animal in question. The 'abnormal' columns represent the limits where the animal does experience negative effects.
Drinking water is unsuitable for livestock if:
The goal of water quality testing is to minimise the risks that the animals are exposed to. This means that samples should be taken at high-risk areas:
Poor water quality can lead to a range of different problems. Click here to read more about common problems.
Hardness ≥ 20°D affects water flavour, but animals are known to adapt. At levels exceeding 25°D, the animals will start drinking less water.
Very soft water (<4°D) can lead to corrosion of pipes because of lower pH.
Hard water also causes deposits of Ca scaling.
For both pigs and poultry, safe drinking water pH levels are between 5 and 8.5. If the drinking water pH drops below 4 or exceeds 9, its flavour will be poor. The animals will drink less, which will cause them to eat less as well.
The pH of the water depends, among other things, on the water’s buffering capacity, which in turn is determined by the hardness of the water: the harder the water, the higher the buffering capacity. Very soft water with a hardness of 0°D will lack any buffering capacity. Small changes are then able to lead to significant increases in acidity which may cause corrosion to the pipes. A hardness of 4°D is required to prevent damage to the drinking water system.
Iron (Fe) is very common in drinking water, although concentrations vary by region. It may cause:
Manganese (Mn) is also quite common, and once again regional differences apply. At levels of >2 mg/L manganese may: