Protecting Drinking Water Supplies

Drinking Water Safety Plans

A water supply is deemed 'safe' if it meets the relevant drinking water quality standards at the tap and 'secure' if a risk management system, a Drinking Water Safety Plan (DWSP), is in place. A DWSP identifies all potential risks to the water supply, from catchment to consumer, and mitigation measures and procedures are put in place to manage these risks. 

In 2009 the World Health Organisation (WHO) published detailed guidance on the implementation of the Drinking Water Safety Plan approach, the document is entitled "Water Safety Plan Manual: step-by-step Risk Management for Drinking Water Supplies".  The primary objective of this approach is to protect human health.  The approach applies equally to small and large drinking water supplies.

The EPA has adopted the WHO's Water Safety Plan approach (see EPA Drinking Water Advice Note No. 8).  The advice note is intended to give an overview of the steps involved in constructing a DWSP and an outline of what it should contain.  DWSPs are also covered in Section 10 of the EPA's Handbook for Public Water Supplies. The EPA has also produced guidance on radiological hazards and associated risks for the purpose of developing DWSPs (see Hazardous Event CO107 Guidance: Geological Characteristics Causing Contamination; Hazardous Event CO220 Guidance: Nuclear Incident Causing Contamination and Hazardous Event Guidance: Vandalism Causing Deliberate Contamination of the Water Supply – i.e. the Raw Water Source, Raw Water Storage or Treated Water in Service Reservoirs or Water Towers).

In Ireland, responsibility for the development and implementation of DWSPs for public water supplies rests with the water supplier, Irish Water. The output from the DWSP process will be used to prioritise remedial works for supplies that need it most and drive improvements in the provision of consistently safe and secure drinking water nationally.

Irish Water will take the lead in the implementation of the DWSP approach for public water supplies but it will be required to co-operate with stakeholders in the catchment including government agencies, industry, farmers, landowners, environmental non-government organisations, recreation/sporting bodies, etc.  These stakeholders will assist in the identification and mitigation of hazardous events in the catchment.  Successful engagement of such stakeholders will serve a dual role or improving raw water source protection for the supply as well as assist in meeting the Water Framework Directive requirements of maintaining or improving water quality status.

Open and transparent implementation of the DWSP approach will increase the consumer’s confidence in the water supplier and will also bring about a greater understanding and awareness amongst all stakeholders involved from source to tap in their role in the protection of our water resources and ensuring that our water supply is consistently safe to drink.

A DWSP should be constantly reviewed and updated to ensure that it delivers a safe and secure water supply.

Protection of Drinking Water from Pesticides

An increase in the number of public water supplies affected by pesticide exceedances has been noted in recent years, in particular the herbicide MCPA.  EPA Advice Note No. 13 "Pesticides in Drinking Water" sets out the actions to be taken where pesticides are detected.  A "National Pesticides in Drinking Water Action Group" has been established to support the achievement of compliance with the Drinking Water Directive's pesticide limit.  The Group is now chaired by the Department of Agriculture, Food and the Marine and membership of the group comprises experts from the HSE, National Federation of Group Water Schemes, Local Authorities Water and Communities Office (LAWCO), Teagasc, IFA, ICMSA, Department of Agriculture's Pesticides Registration & Control Division, Federation of Agrochemical Retail Merchants (FARM), Aminal and Plant Health Association (APHA), Irish Water, CCMA/LGMA and the EPA.  The Group's main aims are to enhance collaboration, including linkages with other national groups, and to support awareness-raising around responsible pesticide and herbicide use, educating pesticide users on the potential impacts of pesticide use on drinking water quality.  Early in its existence, the Group prepared a series of leaflets under the title "Protecting Drinking Water from Pesticides" aimed at promoting responsible pesticide use by both professional and household users.

A Joint Position Paper has been developed by the Health Service Executive (HSE) and the Environmental Protection Agency (EPA). It provides a summary of the issues in relation to pesticides in drinking water including health, legislation, and interventions.

Protecting Drinking Water from Pesticides - Leaflet Series

Herbicide Use in Grassland (including MCPA).
Advice for Farmers and other Professional Users.
Advice for Gardeners and Household Users.
General awareness-raising poster.