EPA investigating persistent discolouration of drinking water on Cork City's northside

Uisce Éireann says water it is pumping uphill dislodges deposits in Cork's ageing cast iron mains, turning the water brown

Brown water on the northside of Cork City

The Environmental Protection Agency (EPA) has an “open investigation file” in relation to the persistent discolouration of the drinking water which is being supplied to hundreds of homes in Cork City.

But the environmental watchdog said it does not generally become involved in investigating an issue further that should be resolved by Uisce Éireann until the utility has been given an opportunity to investigate and resolve it.

The company says it is taking steps to try to resolve the matter following the second major spike in complaints about brown water affecting vast swathes of the city, most on the northside, since the commissioning of the city’s new water treatment plant on the Lee Road in July 2022.

The EPA said monitoring of the public water supply to date indicates that the water being produced at the new plant is fully compliant with drinking water regulations.

“Uisce Éireann are providing regular updates to the EPA on the issue,” the agency said in correspondence to Independent councillor Ken O’Flynn. “Uisce Éireann have confirmed that consultation has taken place between the HSE and Uisce Éireann in relation to public health advice.

“To date there have been no ‘boil water notices’ or ‘do not consume’ notices placed on the Cork city public water supply as a result of discoloured water. 

“Uisce Éireann are required to continue to notify the EPA of any exceedances of the parameters listed in the drinking water regulations and to consult with the HSE in relation to any risk to public health.”

However, one woman, whose mother has dementia and who lives alone with family support, said such advice is useless to her and to other vulnerable people.

“We call to her regularly but we are not there 100% of the time and comments like ‘the water is safe once it runs clear’ doesn’t factor in people like our mum,” the woman said. 

“Mum has dementia and doesn’t have the capacity anymore to be able to apply that advice. It’s just not good enough.”

Complaints about discolouration of the city’s public water supply surged in August 2022 just weeks after the new water treatment plant was commissioned. Uisce Éireann blamed these problems on changes it made to the chemical treatment regime used to rebalance the pH of the drinking water produced at the plant.

The treated water reacted with historic deposits which have built up in the near century-old cast iron mains network, dislodging those deposits and turning the water brown.

The issues were resolved after a few weeks.

But brown water began to flow again in recent weeks, prompting another big spike in complaints from suburbs across the city’s northside.

Uisce Éireann told the Irish Examiner last week the latest problems occurred following a change in the pumping regime used to get the water from the treatment plant uphill to the three reservoirs on the northside.

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The water was being pumped through the ageing network at a higher velocity, again stripping deposits from the inside of the pipes.

Uisce Éireann says it has been responding to the latest complaints in a targetted way, by actively flushing the network in affected areas. It also deep-cleaned the reservoirs.

The utility has advised people not to not drink discoloured water — to run the tap for several minutes to see if it runs clear — and if it doesn’t, to call them on 1800 278 278 with details of dates, times, frequency, and duration of events.