| Characteristic | 1993 | 1994 | 1995 | 1996 | 1997 | 1998 | 1999 | 2000 | 2001 | 2002 | 2003 | 2004 | 2005 | 2006 | 2007 | 2008 | 2009 | 2010 |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Type of standard violated | ||||||||||||||||||
| All health-based standards | 18.0 | 14.5 | 10.4 | 9.4 | 9.1 | 8.0 | 7.3 | 7.9 | 4.9 | 10.0 | 8.0 | 8.2 | 10.9 | 9.5 | 7.5 | 6.3 | 7.2 | 6.7 |
| Lead and copper | 2.8 | 1.7 | 1.9 | 1.7 | 1.7 | 1.5 | 1.4 | 1.2 | 1.0 | 0.8 | 0.6 | 0.8 | 0.7 | 0.4 | 0.4 | 0.5 | 0.8 | 0.2 |
| Total coliforms | 9.1 | 7.6 | 4.0 | 4.1 | 3.5 | 2.9 | 3.1 | 2.8 | 2.1 | 2.5 | 3.0 | 3.4 | 3.2 | 2.3 | 2.3 | 2.3 | 2.5 | 2.4 |
| Chemical and radionuclide | 1.1 | 0.9 | 1.3 | 0.8 | 1.0 | 0.9 | 0.7 | 0.7 | 0.7 | 0.8 | 0.8 | 1.1 | 1.0 | 1.2 | 1.2 | 1.1 | 1.1 | 1.1 |
| Surface water treatment | 6.1 | 5.2 | 3.9 | 3.5 | 3.2 | 2.6 | 2.3 | 3.0 | 1.1 | 4.7 | 1.4 | 1.3 | 4.2 | 4.0 | 2.4 | 1.2 | 1.9 | 2.0 |
| Nitrate/nitrite | 0.3 | 0.1 | 0.2 | 0.2 | 0.3 | 0.6 | 0.3 | 0.5 | 0.2 | 0.2 | 0.3 | 0.1 | 0.1 | 0.5 | 0.2 | 0.1 | 0.1 | 0.1 |
| Disinfection byproducts | — | — | — | — | — | — | — | — | — | 1.4 | 2.8 | 2.4 | 2.0 | 1.5 | 1.4 | 1.4 | 1.2 | 1.1 |
| — Not available. | ||||||||||||||||||
| NOTE: A new standard for disinfection byproducts was implemented beginning in 2002 for larger drinking water systems and in 2004 for smaller systems. Revisions to the standard for surface water treatment took effect in 2002. A revised standard for radionuclides went into effect in 2003. A revised standard for arsenic (included in the Chemical and radionuclide category) went into effect in 2006. No other revisions to the standards have taken effect during the period of trend data (beginning with 1993). Data have been revised since previous publication in America's Children. Values for years prior to 2010 have been recalculated based on the standard in effect for that year and updated data in the Safe Drinking Water Information System. | ||||||||||||||||||
| SOURCE: Environmental Protection Agency, Office of Water, Safe Drinking Water Information System. | ||||||||||||||||||
