Urban and Rural Water Pollution

Pollution can be caused by many different things in many different areas. In cities, outflows from sewage treatment and industrial plants are the main causes of pollution. Also, run-off from roads can wash oil into nearby watercourses. The expanse of concrete infrastructure prevents rainwater and snow from soaking into the ground.

In rural areas, much of the pollution originates from animal wastes and commercial fertilisers. To a lesser extent, groundwater contamination also occurs in this sector as a result of inadequate percolation at septic tanks and from leaching of water soluble plant nutrients from the soil. Additional sources of water pollution can be found on the SWAN website.

With such varied sources of pollution, it is a continual challenge for Irish Water to maintain microbiological quality. In rural private group water schemes, which  are formed by two or more households coming together to provide their own common water supply, it is even more challenging due to the remote nature of many schemes. In such areas, it is critical that the scheme members are vigilant and ensure regular testing and maintenance of treatment works to maintain water quality. More information can be found at the Department of the Environment's Rural Water Programme.

Common contaminants

E Coli bacteria, artificially coloured under an electron microscope


Infectious diseases caused by bacteria like E Coli and parasites like Cryptosporidium are the most significant health risk indicators associated with contaminated drinking water. These contaminants are of particular danger to children, older people, pregnant women and people whose immune systems are compromised. Boil water notices are the short-term remedy, although proper treatment and/or treatment at source are the primary long-term measures.


Lead piping and lead-lined water tanks were commonly used up to about 1970. People getting water through these older plumbing systems will be vulnerable to lead poisoning. The legal level of lead in drinking water is 10 micrograms per litre. It reduced from 25 micrograms per litre on 25 December 2013.

The latest water quality reports for Ireland can be viewed here

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