A contamination scare in the west of Ireland has seen bottles of holy water being replaced.
Water plays an important role in Christian rites
Up to 90,000 homes and businesses are at at risk from cryptosporidium pollution in County Galway, which experts believe could last for up to six months.
The parasite causes severe stomach pains and diarrhoea and has made more than 120 people in the area ill.
Catholic Church authorities are also taking the issue seriously and have decided to use spring water rather than tap in an Easter ceremony.
About 3,000 bottles of holy water are blessed on Holy Saturday, the day before Easter, in Tuam, County Galway.
Father Stephen Farragher, administrator at Tuam Cathedral, said that although Catholics blessed themselves with consecrated water, some people had been known to also drink it.
He said that in particular it would be children who came across the bottles who would be more likely to try a taste.
"We fill about 3,000 holy water bottles and these are blessed on Holy Saturday," he said.
"But we felt there was a public health issue because I have seen people drinking holy water.
"And experience has taught us that these holy water bottles can end up anywhere.
Church authorities have decided to use spring rather than tap water
"I got a photograph a few years ago of a woman who visited Elvis's grave at Graceland and in the photograph was a bottle of holy water from the Cathedral in Tuam."
He told the BBC News website that the increase in the demand for bottles of holy water flew in the face of declining church attendances.
When they first started bottling the holy water only 150 bottles were needed, but that has risen to 3,000.
"There are people who use it when they want cars blessed, and it can end up in glove compartments for luck," he said.
Ireland's Environment Minister Dick Roche has said he plans to travel to Galway to personally examine efforts to deal with the contamination.
Green Party Mayor of Galway Niall O Brolchain called for emergency funding to speed up work on providing safe drinking water.
"I cannot stress strongly enough the importance of dealing with this issue. It must be dealt with quickly and firmly," Mr O Brolchain said.
Galway's publicans say they will seek a rebate on their water charges.
The Irish Hotels Federation also issued warnings to all its members within the contaminated zone to put guests on alert.
Visitors are being told to use boiled or bottled water even when brushing teeth, washing food or making ice cubes.
Hotels have also been asked to tell residents that while it is safe to take a bath, they should not swallow shower or tap water.