Irrigation water quality is an essential factor in plant vitality. Different quality criteria can be specified depending on use. As a result, the quality standards for hydro and pot cultures are very high, while the standards for outdoor use are less strict.

In general, water contains a variety of salts and minerals, the total content of which can indicate the possible effect it might have on plant root systems. This is relatively easy to determine by measuring the water’s electric conductivity (EC). However, such salts can also be analysed individually. Salts of the elements calcium and magnesium, the sum of which also defines water hardness, have the highest importance in terms of levels. Carbonates are the most important (carbonate hardness).

These requirements for clean water and water suitable for animals are not defined in any more detail in the Animal Feed Act. Germany has submitted a proposal for orientation values to the European Commission to assess compliance to these criteria, which are used by the Austrian Feed Inspection body to categorise the suitability of trough water in this manner.

This proposal lists general criteria on flavour, tolerance and usability and also criteria on microbiological, chemical and physical quality. This includes conductivity, pH value, soluble salts, heavy metals, trace elements and minerals. Information on the hygiene quality of trough water can be found on the website of the Federal Ministry of Nutrition, Agriculture and Consumer Protection in Germany.

Protecting local groundwater and its quality has top priority in Austria. A legal framework including the Water Act and systematically promoted activity programmes such as ÖPUL make nationwide groundwater protection possible.

Yet, risks continue to exist due to new agricultural management activities,  but also as a result of climate change, which may, in turn, lead to changes in the use of the land.

A number of organisms that can damage cultivated crops have their habitats (also) in bodies of water and could reach the plants and affect them when water is transported to cultivation areas or used on them.

Such organisms include, for example, phytophthora types that may live in water tanks and heated reservoirs and can be spread over crops through irrigation. 

Furthermore, bacteria that are damaging to plants (e.g. Ralstonia solanacearum, causes bacterial wilt) can also survive to some extent in running and/or standing water.