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File photo of Dublin Bay. Shutterstock/David Soanes
Irish Water

'It's a real crisis': Billions of litres of untreated water overflows at Ringsend wastewater plant since 2015

New figures show the extent of overflows at the plant in recent years.

UNTREATED WASTEWATER HAS overflowed into Dublin Bay from the Ringsend Wastewater Treatment Plant (WWTP) more than 100 times since the beginning of 2015.

Figures seen by show that billions of litres of untreated waste water have overflowed from the plant into the Liffey estuary in recent years, sparking concerns from politicians and environmental groups.

The overflows include the discharge of more than 320 million litres of wastewater into Dublin Bay on seven occasions in 2019 alone, with dozens more overflows in previous years.

The plant, which is operated by Celtic Anglian Water, treats around 40% of Ireland’s sewage and frequently suffers from overflows as a result of storms because it is running beyond capacity.

Data obtained from Irish Water following an Access to Information on the Environment (AIE) request now shows the extent of those overflows over the past number of years.

According to the figures, there have been overflows on 104 occasions since 2015, which have seen more than 9 billion litres of untreated waste water discharged into the Liffey estuary from storm holding tanks at Ringsend WWTP, including:

  • 2.8 billion litres discharged on 30 occasions in 2015
  • 3.1 billion litres discharged on 35 occasions in 2016
  • 1.2 billion litres discharged on 14 occasions in 2017
  • 2 billion litres discharged on 18 occasions in 2018
  • 320 million litres discharged on seven occasions in 2019

Figures also show that on 37 occasions – more than a third of the total over the four-and-a-half year period – over 100 million litres of untreated water were discharged from the plant in a single day.

Of these overflows, 13 occurred between 24 December 2015 and 11 January 2016, when almost 3 billion litres of untreated storm water was discharged from the plant in total.

Green Party leader Eamon Ryan, whose constituency the plant is based in, told that the data showed there was a “real crisis” in the area.

“The plant is overflowing into a UNESCO biosphere, where people are also swimming and surfing and using the beach,” he said.

“The operators have real questions to answer here, such as why such continuous discharges are happening. 

“Celtic Anglian and Irish Water really need to come out and give a more detailed explanation and to take action to reduce the amount that’s overflowing if they can.”

Storm holding tanks

Much of the wastewater from the plant comes via Dublin’s sewer system built in the 1900s which carries water from homes, businesses and water that is drained off roads.

During heavy and sustained rainfall, the amount of water that enters the sewer network can be more than the capacity of the plant, which uses so-called storm water holding tanks to hold excess water that is waiting to be treated.

However, overflows occur when Irish Water releases the excess water from these tanks into the Liffey estuary, in order to prevent the entire sewer network from becoming backed up, which would lead to flooding of roads and properties.

According to the Environmental Protection Agency (EPA), the overflow of untreated wastewater is occurring because Ringsend WWTP is not big enough to consistently treat all of the wastewater that it receives to the necessary standards.

The plant is designed to treat wastewater from a population of about 1.64 million people, but according to figures supplied by the agency, the load entering the plant comes from a population equivalent of around 2.3 million people.

Although the figures obtained by show that the number of overflows at the plant has fallen in recent years, other incidents since last year have seen the closure of some bathing areas in Dublin and criticism of Irish Water for a lack of transparency.

Last month, Green Party councillor Claire Byrne told’s sister site Noteworthy that Irish Water should “come clean” on any issues with the plant.

EPA inspection reports detail how the plant is regularly found in breach of requirements set out in its licence, because it is emitting higher-than-permitted levels of Nitrogen, Phosphorus, the bacteria E.Coli and other “solids”.

Last year, Irish Water reported deposits of “faecal solids” and scum in the water around the plant, while the European Environment Agency has also found Ringsend to be one of the top water-polluting industrial plants in Europe.

In February and earlier his month, the public only became aware of apparent issues at the plant after discoloured water was photographed discharging into Dublin Bay by amateur photographers.

However, a spokeswoman for Irish Water told that discolouration in February and in early July were not overflows, and stated that overflows which do occur in extreme weather conditions should have “no lasting effects on bathing waters”.

“The tide will wash out the spill and the salt water and sunlight acts to clean the water,” the spokeswoman said.

“Irish Water apologises for any inconvenience caused and regrets the impact that overflow incidents may have on beach users.”

DJI_0625 Discoloured water pictured flowing into the River Liffey from the Ringsend plant earlier this month Dublin City Shots Dublin City Shots

Planned upgrade

But environmental campaigners have expressed concerns about the ongoing impact of sewage overflows.

Sinead O’Brien of the Sustainable Water Network said the situation in Dublin Bay was “extremely serious” from a health perspective.

“The network of sewage treatment systems and pipes is in extremely poor condition and will require hundreds of millions of euro to fix,” she said.

“The state is not providing enough investment quickly enough for urgent and crucial upgrade works.”

Irish Water’s spokeswoman said the utility is investing over €400 million to upgrade the plant, which will see an increase in capacity and fewer such incidents in future.

The upgrade works are expected to begin at Ringsend begin this year, but an inspector for An Bord Pleanála found that they will likely lead to an increase in the number of overflow incidents and a reduction in the quality of water that is treated for a time.

The inspection report reads:

During the construction phase, in the winter of 2019/2020… some processes would be removed on a phased basis resulting in reduced treatment capacity and hence a reduction in the final effluent quality is predicted….
Similar to my consideration of the impact on recreational water based activities… I would be more inclined to conclude that this impact would be ‘moderate’ rather than ‘slight’ in terms of significance on the water environment.

However, the inspector did note that while temporary impacts on marine ecology could arise, the duration of the works and the magnitude of their impact would not be of a sufficient scale as to result in adverse significant effects.

A spokeswoman for the EPA also said that discharges from storm water overflows are not considered as environmental incidents and therefore not reportable to the EPA.

Other campaigners have simply called for the utility to be more transparent about overflows, both at the plant and along the sewer system.

“The main treatment plant is out at Ringsend, and it washes out to sea,” said Karin Dubsky, director of the NGO Coastwatch.

“But other parts of the sewer system that overflows go directly into Dublin’s bathing area, where it has a cumulative impact.”

Dubsky said that despite reports of overflows at the Ringsend plant, other overflows in different parts of the system were not being reported.

She suggested that a reporting system for these overflows – like an SMS alert – should be set up, while the government could also introduce an environmental tax on wet wipes, which are responsible for a significant number of blockages in the system.

“The government is running campaigns about wet wipes to tell people not to flush them; but they need to hit people now,” she said.

“They should do it fast, during the summer holidays, while people know the impact it’s having on beaches.”

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