Pharmaceuticals and drinking water


The possibility that pharmaceuticals may get into drinking water has been the subject of research since the 1960s.

The main sources of trace pharmaceuticals in the water environment arise from a combination of raw sewage, disperse occurrence from veterinary use caused by manure spreading and wastewater effluents.

One pharmaceutical which has been a focus of concern is the oestrogen component of the birth control pill. Oestrogens belong to a group of substances known as endocrine disrupters which are known to have the potential to impact on the aquatic environment, such as species of fish. More information on endocrine disrupters sometimes known as EDCs can be found in our consumer leaflet.


Researchers have developed highly sensitive analytical methods to detect various pharmaceutical components, including ethynyl oestradiol (an active ingredient of the most popular brands of birth control pill). The methods can detect sub-nanogram (below parts per trillion) concentrations in samples of water.

Studies[1] have assessed the risk of likely specific pharmaceuticals which may be introduced into source waters via wastewater discharges and has included both desk based and monitoring studies. These studies have concluded that the non or very low detectable levels of pharmaceuticals in drinking water do not pose an appreciable risk to human health.

How do water companies protect drinking water?

By law water companies must assess the risk from pharmaceuticals being present in source waters and where a risk is identified they must monitor the water and have suitable water treatment in place.

The research and monitoring by water companies means that the public can be confident that pharmaceutical residues are not present in drinking water at levels which would pose a risk to health.

  1. Toxicological evaluation for pharmaceuticals in drinking water (

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