The EPA has revised the Drinking Water Quality Standards (飲用水水質標準) three times since its promulgation in 1998. However the increasing number of science and technology parks as well as the increasing complexity of high tech production in recent years are having a greater effect on natural water bodies. To prevent high tech industrial effluent from endangering the safety of drinking water, the EPA has referred to drinking water quality standards of the World Health Organization, the EU, North America, Japan and many advanced European nations in its decision to add molybdenum and indium to Taiwan's list of control standards.

The EPA states the main purpose of this revision is to address pressing concerns about the safety of the nation's drinking water quality. After assessing the domestic situation and the feasibility of testing technology, pollution sources from semiconductor manufacturers, optoelectronics and component manufacturers within five kilometers upstream of tap water purification facilities should be regularly tested for molybdenum and indium. The control standards are set at 0.07 mg/l for molybdenum and 0.07 mg/l for indium, and are slated to take effect upon promulgation of these proposed revisions.