Main drinking water problems

Year of reported problem is not the same for each country: range of reported years, mid-1990s to 2001. Yellow countries have not reported the particular problem. A country was included if it was reported that there was a national problem with a particular contaminant and/or there were problems in particular areas or situations. For example, Estonia: nitrates arising from areas of intensive agricultural land use; and, Finland: nitrate problems in some private wells or boreholes used for water supply.