Mayor of Galway Tom Costello says he will be demanding a "full explanation" for the latest contamination of Galway's water supply at an emergency meeting with management today.
Local authority officials face a series of questions from angry councillors at the emergency session, which will be held in City Hall, Galway, this afternoon.
However, it has been suggested that the city council may avoid prosecution by the Environmental Protection Agency (EPA) under new drinking water legislation if it admits to accidental contamination by its contractors.
Some 15,000 people living in the city's largest suburb, Knocknacarra, were informed by leaflets yesterday that they will have to boil water, due to detection of high levels of E.coli in the public water supply earlier this week.
No illness has as yet been traced to the new contamination, but the city council's delay in notifying the HSE West about the problem will be one of the issues debated at the session.
Officials will also be pressed on their suggestion that it may have been caused by local authority infrastructural works in the Knocknacarra area.
The E.coli contamination comes just a month after the lifting of the boil water notice for 70,000 people living in the city and western outskirts.
That five-month alert resulted in 242 laboratory-confirmed cases of cryptosporidiosis and the hospitalisation of people due to infection with the cryptosporidium parasite. Children under-10 were among the most seriously affected and some youngsters may develop long-term complications.
The majority of all cases were linked to sewage contamination. However, no sources within the Corrib system have been identified by the local authorities to date.
Minister for the Environment John Gormley received a briefing on the fresh crisis from his party colleague, Cllr Niall Ó Brolcháin. The Department of the Environment said it was monitoring the situation with the local authority.
Labour Party president and Galway West TD Michael D Higgins has called for an "immediate and thorough investigation" into the circumstances of the latest water contamination.
The Environmental Protection Agency said it has also been notified and is liaising with HSE West and Galway City Council.
The EPA has held enforcement powers in relation to drinking water quality since last March, and is currently assessing the situation in relation to the cryptosporidium outbreak in Galway. However, it would not have the powers to prosecute if the local authority admitted to contamination, the agency said.
Cllr Ó Brolcháin has called on Mr Gormley to take action, including a 12-point plan drawn up with former environment minister Dick Roche to be fully implemented in as "short a timeframe as possible". A serious effort must also be made to discover the source, he said.
E.COLI: creates toxin
E.coli is short for Escherichia coli, a bacteria or germ which causes severe diarrhoea and cramps. It can be contracted by eating contaminated or undercooked food, drinking contaminated water or unpasteurised milk, or working with cattle. One of the most serious strains is E.coli 0157, which can produce a toxin causing severe symptoms of gastroenteritis - and can also lead to complications related to kidney function. Most infected people can recover without antibiotics or specific treatment within five to 10 days.