March 15, 2007:HSE West issues "boil water" notice for 90,000 residents in Galway city and county, due to unseasonal rise in illness caused by the cryptosporidium parasite.
March 16:Alert extended to residents in south Mayo relying on Corrib system.
March 22:EPA says it identified Galway city's supply as being at "very high risk" of cryptosporidium contamination in 2005.
March 28:Cryptosporidium hominis, the strain linked to human sewage, confirmed for the first time in some of 80 cases identified by laboratory since January.
March 29:Political row erupts as then minister for the environment Dick Roche claims €21.5 million allocated to upgrade Galway waterworks has not been drawn down.
April 18:Mr Roche allocates additional €1 million to deal with water contamination.
April 23:Some 150 people protest outside Galway City Hall over the crisis.
April 30:HSE West estimates up to 2,000 people may have the illness. Children under 10-years-old the main victims among 210 laboratory-confirmed cases.
July 9:Alert lifted for 20,000 people in county border area east of city.
August 20:Alert lifted for 70,000 people in remaining affected areas.