Finian McGrath (Dublin North Central, Independent)
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840. To ask the Minister for Environment, Community and Local Government his views on a matter (details supplied) regarding the chemicals to treat Ireland’s drinking water system; and if he will make a statement on the matter. [11247/15]

Alan Kelly (Tipperary North, Labour)
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The selection of appropriate water treatments to ensure the quality of the drinking water is made by water suppliers on an individual supply by supply basis, based on a number of factors including assessment of catchment and source risks with respect to the clarity, organic content, and the likely risk of pathogenic micro-organisms in the source water.

Under the European Union (Drinking Water) Regulations 2014, a copy of which is available in the Oireachtas library, suppliers of drinking water are required to ensure that the water supplied is wholesome and clean. Water which is wholesome and clean is defined as water which is free from any micro-organisms and parasites and from any substances which, in numbers or concentrations, constitute a potential danger to human health and which meets the quality standards specified in the Schedule to the Regulations. Maximum microbiological, chemical and indicator parametric values are set out in tabular form in the Regulations including 26 chemical parameters. However, this does not mean that the same chemicals are used in the treatment of drinking water. Many of the chemicals listed in the Regulations are elementary substances and as such are part of the natural environment and can be expected to be present in drinking water in small quantities, with no risk to human health as long as parameter values are not exceeded.

Regulation 13 of the Regulations requires all water suppliers to ensure that substances used in the preparation or distribution of water intended for human consumption, or impurities associated with such substances, do not, either directly or indirectly, reduce the protection of human health provided for in the Regulations. Regulation 13 also provides that water suppliers must take all measures necessary to ensure that the efficiency of disinfection treatment is verified and that any contamination from disinfection by-products is kept as low as possible without compromising the disinfection.

The Environmental Protection Agency (EPA) is the supervisory authority with responsibility for monitoring Irish Water's compliance with the regulations. The EPA has published a manual to assist Irish Water and private water suppliers in designing and operating water treatment systems to provide rigorous disinfection, whilst maintaining compliance with other water quality parameters, particularly in relation to disinfection by-products. The manual can be downloaded from:

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