Tritium has leaked from 48 of 65 nuclear sites in the US. In one case, leaking water contained  of tritium per liter, which is 375 times the current EPA limit for drinking water, and 28 times the World Health Organization's recommended limit. This is equivalent to  or roughly 0.8 parts per trillion.
The US Nuclear Regulatory Commission states that in normal operation in 2003, 56 pressurized water reactors released  of tritium (maximum: ; minimum: ; average: ) and 24 boiling water reactors released  (maximum: ; minimum: 0 Ci; average: ), in liquid effluents. 40,600 Curie of tritium are approximately equivalent to 
According to the U.S. Environmental Protection Agency, self-illuminating exit signs improperly disposed in municipal landfills have been found to contaminate waterways.