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Water Quality

Water Quality

Ireland is fortunate to have safe and reliable sources of fresh, raw water that we can treat and use as drinking water. However, there are many different factors that can have an impact on the quality of drinking water, for example soil or rock types, land use practices and even high rainfall can all affect the quality of drinking water.

When we turn on the tap, we all expect to be assured of clean, safe drinking water being delivered to our homes and businesses every day and it’s important to remember that there is a complex process behind the treatment, monitoring and testing of our drinking water in Ireland.


What is tested for in drinking water?

Drinking water parameters are tested for in drinking water samples to ensure that the drinking water quality is of an acceptable standard, as set out in the European Union Drinking Water Regulations 2014 legislation.

A drinking water exceedance is a result from a drinking water sample which is above the acceptable limit.

The HSE carry out the monitoring programme on behalf of Mayo County Council, for group water schemes, in accordance with this legislation.


Drinking water parameters are grouped into 3 categories:

1. Indicator parameters are usually tested along with microbiological and chemical parameters in a water sample. These parameters may not necessarily pose a risk on their own, but they can indicate the presence of other potentially more harmful parameters in a water sample.

2. Chemical parameters are tested in drinking water samples to determine if any chemicals present are within acceptable limits. Chemical parameters that are present in drinking water samples can be caused by chemicals dissolving into water from pipes, chemicals carrying over from water treatment processes, chemical reactions that can occur between different materials in the water, or even runoff from farms.

3. Microbiological parameters are microorganisms (i.e. bacteria) that are tested in drinking water. The presence of these parameters in a drinking water sample may indicate that contamination may have occurred either at a water source or within the water distribution network.


Check Your Water Quality

The Irish Water website allows you to search for your Water Supply Zone (WSZ) using the address search tool or by using the map to access the drinking water quality information for your area.

Please use the following link to get more information on your WSZ and the results for your area.


Group Water Schemes

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