Paul Melia of the Irish Independent reports a Cryptosporidium outbreak that resulted in 120,000 people being forced to boil their water for five months cost €19m, a new study shows.

The 2007 outbreak in Galway cost each household €95 and resulted in one in eight hotel and guesthouse bookings being cancelled.

One in five people in the city refuse to drink the tap water today due to concerns about its safety, the study says.

It found that had the water supply to the city and surrounding areas been subjected to an adequate treatment process costing just €1.6m, it would have resulted in an €11 saving for every €1 invested.

The ‘Economic Assessment of the Waterborne Outbreak of Cryptosporidium Hominis in Galway 2007’ study, which was funded by the Environmental Protection Agency (EPA), says the outbreak lasted for 158 days and resulted in 242 confirmed cases of cryptosporidiosis, “although it was likely the actual number affected was far higher”.

– There were 242 notified cases of cryptosporidiosis, with another 497 non-reported cases.

– 45,160 households were affected, and around 120,000 people.

– There was an 80pc increase in bottled water consumption during the outbreak, with a spend of €3.5m. Another €400,000 was spent boiling water.

– Hotels and guesthouses were obliged to provide 4.2 litres of water per day to guests, and the hospitality industry bore costs of €50,000 per day.

Cryptosporidium remains a problem across the country, with the latest data showing that 17 water supplies require upgrades to remove the threat.

The report, compiled by researchers at NUI Galway with an official from the HSE, found that households bore costs totalling €3.9m, the hospitality sector another €8m, while the local authorities spent almost €6m.