Gwangju City Responds to Tap Water Filter Discoloration Complaints: "Meets Water Quality Standards"

"Turnover" Phenomenon at Juam Dam Due to Temperature Changes
Temporary Detection of Manganese
"Safe for Drinking and Harmless to Human Health... Monitoring to Be Further Strengthened"

Gwangju City Hall exterior view.

The Gwangju City Waterworks Headquarters announced on October 22 that, following recent complaints about discolored shower filters in tap water in certain areas, an emergency water quality inspection was conducted and all tests confirmed that the water met the standards for drinking water quality.

Since receiving the complaints on October 17, the Waterworks Headquarters has conducted daily water quality inspections at each stage of the Deoknam Water Purification Plant. The results showed that a trace amount of manganese (Mn) was temporarily detected on October 17, but none was detected from October 18 onward. In addition, all 54 household water quality tests requested directly by citizens (with 52 completed as of October 21) met the standards for drinking water.

This filter discoloration phenomenon was analyzed to have occurred because a "turnover" event, caused by changes in the water temperature at the Juam Dam water source, temporarily introduced manganese from the sediment layer into the water entering the purification plant.

The Waterworks Headquarters explained that the standard for manganese in drinking water is 0.05 mg/L, and all detected levels were below this threshold. This means there is no harmful effect on human health, and the tap water is completely safe to drink. However, since even trace amounts of manganese can cause filter discoloration, this is believed to be the reason for the color change in some household filters.

The Waterworks Headquarters plans to further strengthen water quality monitoring of both the Juam Dam and the water entering the purification plant to alleviate public concerns. In particular, if high concentrations of manganese are expected, immediate water treatment measures will be implemented to ensure the safety of tap water.

Hong Kitaek, head of the Deoknam Water Purification Plant, stated, "This discoloration phenomenon was caused by manganese levels within the water quality standards and poses no risk to human health," adding, "We will make every effort to ensure continuous water quality management and enhanced water treatment so that citizens can use tap water with peace of mind."