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Drinking Water Quality Standards Revised to Respond to Climate Change

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To respond to climate change, adapt to extreme climate events, and enhance the management of drinking water quality, the EPA amended and announced water quality items in the Drinking Water Quality Standards (飲用水水質標準) for substances that do not affect health, so as to increase the resilience and stability of the water supply while also ensuring the safety and quality of drinking water.   

The Drinking Water Quality Standards were formulated and announced in 1998 by the EPA and have undergone six reviews and amendments since then. At present, there are a total of 68 control items in the Standards. The EPA has been reviewing the Drinking Water Standards in response to the need for adaptation to climate change, technological development and international trends in drinking water management. Natural disasters such as droughts, torrential rains and earthquakes often cause shortages of source water, unstable source water quality and other conditions that affect water treatment and hence drinking water quality. Thus, the EPA announced this amendment and the addition of standards for substances that do not affect health, so as to ensure the sufficiency and quality of drinking water supply during periods of natural disaster response.      

1. The standard for free residual chlorine, when source water turbidity values exceed 1,500 NTU as a result of torrential rains or other natural disasters, was revised. When source water turbidity exceeds 1,500 NTU due to torrential rains or other natural disasters, the turbid water even after purification treatment will still have turbidity values slightly higher than normal. To avoid high-turbidity conditions, in which microorganisms in the water can grow or hide in the pores of suspended particles, it is necessary to increase the amount of chlorine added to the effluent to ensure water quality safety through continuous disinfection. Therefore, to respond and adapt to extreme climate situations, the standard for free residual chlorine was revised to 0.2-3.0 (mg/L). The previous maximum limit was 2.0 (mg/L).


2. Drinking water quality standards were added for tap water supplied by water source zones affected during natural disaster response periods, including:

  • Limit range for free residual chlorine: 0.2-3.0 (mg/L)
  • Physical standards: the maximum limit for turbidity is 4 NTU and for color 10 Platinum-cobalt units
  • Contaminants that cause aesthetic, cosmetic, and technical effects: iron 0.5 (mg/L), manganese 0.1 (mg/L), total hardness as CaCO3 400 (mg/L).

Excerpt from Major Environmental Policies, June 2022

Ministry of Environment